JP4123666B2 - Semiconductor ceramic powder and multilayer semiconductor ceramic electronic parts - Google Patents
Semiconductor ceramic powder and multilayer semiconductor ceramic electronic parts Download PDFInfo
- Publication number
- JP4123666B2 JP4123666B2 JP2000008945A JP2000008945A JP4123666B2 JP 4123666 B2 JP4123666 B2 JP 4123666B2 JP 2000008945 A JP2000008945 A JP 2000008945A JP 2000008945 A JP2000008945 A JP 2000008945A JP 4123666 B2 JP4123666 B2 JP 4123666B2
- Authority
- JP
- Japan
- Prior art keywords
- semiconductor ceramic
- powder
- resistance
- barium titanate
- electronic component
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000000919 ceramic Substances 0.000 title claims description 61
- 239000004065 semiconductor Substances 0.000 title claims description 60
- 239000000843 powder Substances 0.000 title claims description 52
- JRPBQTZRNDNNOP-UHFFFAOYSA-N barium titanate Chemical compound [Ba+2].[Ba+2].[O-][Ti]([O-])([O-])[O-] JRPBQTZRNDNNOP-UHFFFAOYSA-N 0.000 claims description 34
- 229910002113 barium titanate Inorganic materials 0.000 claims description 34
- 238000005245 sintering Methods 0.000 claims description 9
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 7
- 239000011164 primary particle Substances 0.000 claims description 6
- 229910052759 nickel Inorganic materials 0.000 claims description 2
- 239000010936 titanium Substances 0.000 description 21
- 239000002245 particle Substances 0.000 description 9
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 238000001354 calcination Methods 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 239000006104 solid solution Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- AYJRCSIUFZENHW-UHFFFAOYSA-L barium carbonate Chemical compound [Ba+2].[O-]C([O-])=O AYJRCSIUFZENHW-UHFFFAOYSA-L 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000011812 mixed powder Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- -1 Ca or Sr and Pb Chemical class 0.000 description 1
- 229910052684 Cerium Inorganic materials 0.000 description 1
- 229910052692 Dysprosium Inorganic materials 0.000 description 1
- 229910052691 Erbium Inorganic materials 0.000 description 1
- 229910052693 Europium Inorganic materials 0.000 description 1
- 229910052688 Gadolinium Inorganic materials 0.000 description 1
- 229910052689 Holmium Inorganic materials 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910052765 Lutetium Inorganic materials 0.000 description 1
- 229910052779 Neodymium Inorganic materials 0.000 description 1
- 229910052777 Praseodymium Inorganic materials 0.000 description 1
- 229910052772 Samarium Inorganic materials 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 229910052771 Terbium Inorganic materials 0.000 description 1
- 229910052775 Thulium Inorganic materials 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical group [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 229910052769 Ytterbium Inorganic materials 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 238000000975 co-precipitation Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 238000007606 doctor blade method Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000002003 electrode paste Substances 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 238000001027 hydrothermal synthesis Methods 0.000 description 1
- 229910052746 lanthanum Inorganic materials 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 238000010405 reoxidation reaction Methods 0.000 description 1
- YZDZYSPAJSPJQJ-UHFFFAOYSA-N samarium(3+);trinitrate Chemical compound [Sm+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O YZDZYSPAJSPJQJ-UHFFFAOYSA-N 0.000 description 1
- 239000011163 secondary particle Substances 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 238000003980 solgel method Methods 0.000 description 1
- 238000010532 solid phase synthesis reaction Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Images
Landscapes
- Compositions Of Oxide Ceramics (AREA)
- Ceramic Capacitors (AREA)
- Thermistors And Varistors (AREA)
Description
【0001】
【発明の属する技術分野】
この発明は半導体セラミック粉末および積層型半導体セラミック電子部品に関し、特に、チタン酸バリウム系の半導体セラミック粉末、および、これを焼結して形成した半導体セラミック層を備え、正の抵抗温度係数を有する積層型半導体セラミック電子部品に関する。
【0002】
【従来の技術】
従来、チタン酸バリウム系の半導体セラミックは、常温では比抵抗が低く、ある温度(キュリー温度)を超えると急激に抵抗が上昇するという、正の抵抗温度特性(PTC特性)を有しており、温度制御、過電流保護、定温度発熱などの用途に広く用いられている。中でも、回路用として用いられている過電流保護用の電子部品において、室温での低抵抗化が要望されている。特に、USB対応のパソコン周辺機器においては、小型で低抵抗、高耐圧の半導体セラミック電子部品が切に望まれている。
【0003】
【発明が解決しようとする課題】
従来、上述のPTC特性を有するチタン酸バリウム系の半導体セラミックは、チタン酸バリウム粉体に、または、炭酸バリウムおよび二酸化チタンの混合粉に、半導体化剤としての金属イオンまたは金属酸化物を混合させ、その粉体より成形した成形物を焼結させることにより、作製されていた。しかしながら、半導体セラミックを作製する際に、チタン酸バリウム粉体を十分に半導体化させずに焼結体を作製したために室温での抵抗が高くなったり、または、室温での抵抗を低くする目的で焼結の温度を高くしたために室温での抵抗は低くなるもののキュリー点以上での抵抗の変化率が低くなったりする場合がある。さらに、チタン酸バリウム粉体を十分に半導体化させるために粉体を高温で焼成したために、セラミック電子部品を作製したときに焼結が進まず室温での抵抗が高くなるなどの問題があった。
【0004】
それゆえに、この発明の主たる目的は、室温での抵抗が低くキュリー温度以上での抵抗の変化率が高い半導体セラミックを得ることができる半導体セラミック粉末を提供することである。
また、この発明の他の目的は、室温での抵抗が低くキュリー温度以上での抵抗の変化率が高い半導体セラミック層を備える積層半導体セラミック電子部品を提供することである。
【0005】
【課題を解決するための手段】
上記目的を達成するために、鋭意研究を重ねた結果、ある限定された物性を有するチタン酸バリウム系の半導体セラミック粉末を用いることによって、小型化かつ低抵抗で、十分な抵抗の変化率を有し、さらには、耐電圧の高い積層型半導体セラミック電子部品が得られることを見出し、この発明を完成するに至った。
すなわち、この発明にかかる半導体セラミック粉末は、チタン酸バリウム粉体100wt%に対して、チタン酸バリウム粉体のTi3+の濃度が0.0003wt%以上であり、Baサイト/Tiサイト比が1.000以上で1.010以下であり、一次粒子径が1.0μm以下であり、ドナー元素が固溶している、半導体セラミック粉末である。なお、以下、Ba/Ti比と表しているものは、Baサイト/Tiサイト比を意味する。
この発明にかかる積層型半導体セラミック電子部品は、交互に積層される複数の半導体セラミック層および複数の内部電極を備える積層型半導体セラミック電子部品であって、半導体セラミック層は、この発明にかかる半導体セラミック粉末を焼結して形成される、正の抵抗温度特性を有する積層型半導体セラミック電子部品である。なお、内部電極は、たとえばニッケルを含有する。
【0006】
チタン酸バリウム粉体の一次粒子径が1.0μmよりも大きいと、焼結が進まず室温での抵抗が高くなり、また、室温での抵抗を下げようとしてより高い温度で焼成すると室温での抵抗は下がるもののキュリー温度以上での抵抗の変化率は低くなってしまう。
また、チタン酸バリウム粉体100wt%に対して、チタン酸バリウム粉体のTi3+の濃度が0.0003wt%未満であると、室温での抵抗が高く、キュリー温度以上での抵抗の変化率が低くなってしまう。
さらに、チタン酸バリウム粉体のBa/Ti比が1.000未満または1.010を超えると、Ti3+がチタン酸バリウム内に十分に存在しかつ平均粒径が1.0μm以下であっても、室温での抵抗が高く、キュリー温度以上での抵抗の変化率が低くなってしまう。
また、チタン酸バリウム粉体の一次粒子径が1.0μmよりも大きいと、半導体セラミック層を薄くすることができず、さらに焼結する際に高温で焼成しなければならない。
【0007】
この発明の上述の目的、その他の目的、特徴および利点は、図面を参照して行う以下の発明の実施の形態の詳細な説明から一層明らかとなろう。
【0008】
【発明の実施の形態】
図1はこの発明にかかる積層型半導体セラミック電子部品の一例を示す図解図である。図1に示す積層型半導体セラミック電子部品10は積層体12を含む。積層体12では、複数の半導体セラミック層14と複数の内部電極16とが交互に重ね合わされている。この場合、1つおきの内部電極16は積層体12の1つの側面にまで形成され、残りの内部電極16は積層体12の他の1つの側面にまで形成される。さらに、積層体12の1つの側面および他の1つの側面には、外部電極18aおよび18bがそれぞれ形成される。この場合、一方の外部電極18aは1つおきの内部電極16に接続され、他方の外部電極18bは残りの内部電極16に接続される。
【0009】
上述の積層型半導体セラミック電子部品10の半導体セラミック層14は、チタン酸バリウム系の半導体セラミック粉末を焼結して形成される。このチタン酸バリウム系の半導体セラミック粉末としては、チタン酸バリウム粉体100wt%に対して、チタン酸バリウム粉体のTi3+の濃度が0.0003wt%以上であり、Ba/Ti比が1.000以上で1.010以下であり、一次粒子径が1.0μm以下であり、ドナー元素が固溶している、半導体セラミック粉末が用いられる。
このチタン酸バリウム系の半導体セラミック粉末において、必要に応じて、Baの一部がCaやSrなどのアルカリ土類金属およびPbなどで置換されてもよく、また、Tiの一部がSn,ZrおよびHfなどのチタン族の元素で置換されてもよい。
また、このチタン酸バリウム系の半導体セラミック粉末に含まれる半導体化剤は、ドナー元素と呼ばれるものであるが、このようなドナー元素としては、La,Ce,Pr,Nd,Pm,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu,Yなどの希土類元素や、Nb,Ta,Bi,Sb,Wなどの遷移金属を用いることができる。
また、このほかにも、このチタン酸バリウム系の半導体セラミック粉末には、必要に応じて、SiO2 やMnなどが添加されてもよい。
上記の半導体セラミック層14を形成するために用いられるチタン酸バリウム系の半導体セラミック粉末は、チタン酸バリウム粉体中にTi3+が重量比で0.0003wt%以上存在し、ドナーが固溶したものであるが、このようなチタン酸バリウム系の半導体セラミック粉末の合成方法については、特に限定するものではないが、たとえば水熱法、加水分解法、共沈法、固相法、ゾルゲル法を用いることができ、必要に応じて仮焼が施される。
また、上述の内部電極16に含まれる導電成分としては、Ni系金属、Mo系金属、Cr系金属、または、これらの合金などを用いることができるが、半導体セラミック層14との間での確実なオーミック接触を可能とする点から、特にNi系金属を用いることが好ましい。
次に、この発明を実施例に基づいてさらに詳細かつ具体的に説明する。
【0010】
【実施例】
出発原料として、BaCO3 、TiO2 、硝酸サマリウム(Sm)溶液を用い、各元素のモル比として、Sm/Ti=0.0012となるように秤量を行い、純水およびPSZ製の直径5mmの玉石を用いて5時間ボールミルによる混合を行った。なお、上記の調合(秤量)時においては、種々のBa/Ti比となるように秤量を行っている。その後、蒸発乾燥を行い、得られた混合粉を1000〜1400℃で2時間仮焼した。この仮焼粉(チタン酸バリウム粉体)に対して、分散剤および純水を混合して5〜80時間粉砕した後、バインダーなどを添加して、スラリーとした後、ドクターブレード法により成形し、グリーンシートを得た。このグリーンシート上にNi電極ペーストをスクリーン印刷して内部電極とした。さらに、内部電極がグリーンシートの一端側および他端側で交互に露出するように複数のグリーンシートを積層し、加圧圧着後、切断して積層体とした。なお、この積層体には、その上下に内部電極を印刷していないダミーのグリーンシートを重ねて圧着している。
次に、この積層体を大気中で脱バインダー処理した後、水素/窒素=3/100の強還元雰囲気中にて2時間焼成を行った。その後、オーミック銀ペーストを塗布して大気中で500〜1000℃で1時間再酸化処理を施し、外部電極を形成して、積層型半導体セラミック電子部品(試料)とした。
【0011】
そして、各試料について、仮焼粉の平均粒径(μm)、仮焼粉のTi3+の濃度(wt%)、室温抵抗(Ω)および抵抗変化率(桁)を測定した。
この場合、仮焼粉の平均粒径は、SEMにより撮影した写真の粒子をデジタイザーを用いて直接測定し、その測定値を対数正規分布により算出した。したがって、この仮焼粉の平均粒径は、仮焼により凝集した二次粒子径ではなく一次粒子径を表している。
また、仮焼粉のTi3+の濃度の測定は、仮焼粉を酸溶解し、溶出したTi3+をFe3+で置換して生成したFe2+を吸光光度計で測定した値である。
さらに、室温抵抗は、デジタルボルトメーターを用いて4端子法で測定した。また、抵抗変化率は、室温(25℃)から250℃までにおける最大抵抗値を室温抵抗値で除し、その常用対数で算出した。
これらの測定結果などを表1に示す。
【0012】
【表1】
【0013】
表1に示す結果から明らかなように、実施例1〜4では、仮焼粉(チタン酸バリウム粉体)の平均粒径が1.0μm以下で、Ti3+の濃度が0.0003wt%以上で、Ba/Ti比が1.000以上で1.010以下であり、得られた積層型半導体セラミック電子部品(試料)について、室温抵抗が0.2Ω以下で、抵抗変化率が2.7桁以上の特性が得られている。
これに対して、比較例1のようにチタン酸バリウム粉体の平均粒径が0.3μmと微粒であってもTi3+が検出できないようなチタン酸バリウム粉体を用いて作製した積層型半導体セラミック電子部品(試料)については、室温抵抗が0.50Ωと高く、抵抗変化率も2.5桁と低くなる。
また、比較例2および3のようにTi3+が十分にチタン酸バリウム粉体内に存在してもチタン酸バリウム粉体の平均粒径が1.0μmを超えると、室温抵抗が高く、抵抗変化率も低くなる。
さらに、比較例4および5のようにBa/Ti比が1.000未満または1.010を超えると、Ti3+がチタン酸バリウム粉体内に十分に存在しかつ平均粒径が1.0μm以下であっても、室温抵抗は1Ω以上と高く、抵抗変化率は2.2以下と低くなる。
【0014】
【発明の効果】
この発明によれば、室温での抵抗が低くキュリー温度以上での抵抗の変化率が高い半導体セラミックを得ることができる。
また、この発明にかかる半導体セラミック粉末を用いれば、室温での抵抗が低くキュリー温度以上での抵抗の変化率が高い半導体セラミック層を備える積層半導体セラミック電子部品が得られる。そのため、この発明にかかる積層半導体セラミック電子部品では、小型かつ低抵抗で高い抵抗変化率を有し得る。
【図面の簡単な説明】
【図1】図1はこの発明にかかる積層型半導体セラミック電子部品の一例を示す図解図である。
【符号の説明】
10 積層型半導体セラミック電子部品
12 積層体
14 半導体セラミック層
16 内部電極
18a、18b 外部電極[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a semiconductor ceramic powder and a multilayer semiconductor ceramic electronic component, and more particularly, to a barium titanate-based semiconductor ceramic powder, and a multilayer having a positive resistance temperature coefficient, including a semiconductor ceramic layer formed by sintering the semiconductor ceramic powder. The present invention relates to a type semiconductor ceramic electronic component.
[0002]
[Prior art]
Conventionally, barium titanate-based semiconductor ceramics have a positive resistance-temperature characteristic (PTC characteristic) in which the specific resistance is low at room temperature and the resistance rapidly increases when a certain temperature (Curie temperature) is exceeded. Widely used in applications such as temperature control, overcurrent protection, and constant temperature heating. In particular, there is a demand for low resistance at room temperature in electronic components for overcurrent protection used for circuits. In particular, in a USB-compatible personal computer peripheral device, a semiconductor ceramic electronic component having a small size, a low resistance, and a high withstand voltage is highly desired.
[0003]
[Problems to be solved by the invention]
Conventionally, a barium titanate-based semiconductor ceramic having the above-described PTC characteristics is obtained by mixing metal ions or metal oxides as a semiconducting agent into barium titanate powder or mixed powder of barium carbonate and titanium dioxide. It was produced by sintering a molded product formed from the powder. However, when producing a semiconductor ceramic, the sintered body was produced without sufficiently converting the barium titanate powder into a semiconductor, so that the resistance at room temperature is increased or the resistance at room temperature is decreased. Although the resistance at room temperature decreases because the sintering temperature is increased, the rate of change in resistance at or above the Curie point may decrease. Furthermore, since the powder was fired at a high temperature in order to fully convert the barium titanate powder into a semiconductor, there was a problem that, when a ceramic electronic component was manufactured, sintering did not proceed and resistance at room temperature was increased. .
[0004]
Therefore, a main object of the present invention is to provide a semiconductor ceramic powder capable of obtaining a semiconductor ceramic having a low resistance at room temperature and a high rate of change in resistance at or above the Curie temperature.
Another object of the present invention is to provide a laminated semiconductor ceramic electronic component including a semiconductor ceramic layer having a low resistance at room temperature and a high rate of change in resistance at the Curie temperature or higher.
[0005]
[Means for Solving the Problems]
As a result of intensive research to achieve the above object, by using a barium titanate semiconductor ceramic powder having limited physical properties, it has a small size, low resistance, and sufficient resistance change rate. Furthermore, the inventors have found that a laminated semiconductor ceramic electronic component having a high withstand voltage can be obtained, and have completed the present invention.
That is, in the semiconductor ceramic powder according to the present invention, the concentration of Ti 3+ in the barium titanate powder is 0.0003 wt% or more with respect to 100 wt% of the barium titanate powder, and the Ba site / Ti site ratio is 1 The semiconductor ceramic powder has a primary particle size of 1.0 μm or less and a donor element in a solid solution. Hereinafter, the expression Ba / Ti ratio means the Ba site / Ti site ratio.
A multilayer semiconductor ceramic electronic component according to the present invention is a multilayer semiconductor ceramic electronic component comprising a plurality of semiconductor ceramic layers and a plurality of internal electrodes that are alternately stacked, and the semiconductor ceramic layer is a semiconductor ceramic according to the present invention. It is a laminated semiconductor ceramic electronic component having a positive resistance temperature characteristic formed by sintering powder. The internal electrode contains nickel, for example.
[0006]
When the primary particle size of the barium titanate powder is larger than 1.0 μm, sintering does not proceed and the resistance at room temperature increases, and when firing at a higher temperature to lower the resistance at room temperature, Although the resistance is lowered, the rate of change in resistance above the Curie temperature becomes low.
Further, when the concentration of Ti 3+ in the barium titanate powder is less than 0.0003 wt% with respect to 100 wt% of the barium titanate powder, the resistance at room temperature is high, and the rate of change in resistance at the Curie temperature or higher. Will be lower.
Further, when the Ba / Ti ratio of the barium titanate powder is less than 1.000 or exceeds 1.010, Ti 3+ is sufficiently present in the barium titanate and the average particle diameter is 1.0 μm or less. However, the resistance at room temperature is high, and the rate of change in resistance above the Curie temperature is low.
If the primary particle size of the barium titanate powder is larger than 1.0 μm, the semiconductor ceramic layer cannot be thinned and must be fired at a high temperature during sintering.
[0007]
The above object, other objects, features, and advantages of the present invention will become more apparent from the following detailed description of the embodiments of the present invention with reference to the drawings.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an illustrative view showing one example of a laminated semiconductor ceramic electronic component according to the present invention. A multilayer semiconductor ceramic
[0009]
The semiconductor
In this barium titanate-based semiconductor ceramic powder, a part of Ba may be substituted with an alkaline earth metal such as Ca or Sr and Pb, if necessary, and a part of Ti is Sn, Zr. And may be substituted with a titanium group element such as Hf.
The semiconducting agent contained in the barium titanate-based semiconductor ceramic powder is called a donor element. Examples of such a donor element include La, Ce, Pr, Nd, Pm, Sm, Eu, Rare earth elements such as Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y, and transition metals such as Nb, Ta, Bi, Sb, and W can be used.
In addition, SiO 2 , Mn, or the like may be added to the barium titanate-based semiconductor ceramic powder as necessary.
In the barium titanate-based semiconductor ceramic powder used to form the semiconductor
Further, as the conductive component contained in the
Next, the present invention will be described in more detail and specifically based on examples.
[0010]
【Example】
BaCO 3 , TiO 2 , samarium nitrate (Sm) solution was used as a starting material and weighed so that the molar ratio of each element was Sm / Ti = 0.0012. Using a cobblestone, mixing was performed by a ball mill for 5 hours. In addition, at the time of said preparation (weighing), it measures so that it may become various Ba / Ti ratio. Then, evaporation drying was performed, and the obtained mixed powder was calcined at 1000 to 1400 ° C. for 2 hours. The calcined powder (barium titanate powder) is mixed with a dispersant and pure water and pulverized for 5 to 80 hours, and then added with a binder to form a slurry, which is then molded by a doctor blade method. A green sheet was obtained. Ni electrode paste was screen-printed on this green sheet to form internal electrodes. Furthermore, a plurality of green sheets were laminated so that the internal electrodes were alternately exposed on one end side and the other end side of the green sheet, and after pressure-bonding, the laminate was cut into a laminate. It should be noted that dummy green sheets on which no internal electrodes are printed are stacked and pressure-bonded on the laminated body.
Next, this laminate was debindered in the air, and then fired in a strong reducing atmosphere of hydrogen / nitrogen = 3/100 for 2 hours. Thereafter, an ohmic silver paste was applied, reoxidation treatment was performed in the atmosphere at 500 to 1000 ° C. for 1 hour, external electrodes were formed, and a multilayer semiconductor ceramic electronic component (sample) was obtained.
[0011]
And about each sample, the average particle diameter (micrometer) of calcining powder, the density | concentration (wt%) of Ti3 + of calcining powder, room temperature resistance (ohm), and resistance change rate (digit) were measured.
In this case, the average particle diameter of the calcined powder was directly measured by using a digitizer for photographic particles taken by SEM, and the measured value was calculated by a lognormal distribution. Therefore, the average particle size of the calcined powder represents the primary particle size, not the secondary particle size aggregated by calcining.
Moreover, the measurement of the Ti 3+ concentration of the calcined powder is a value obtained by measuring the Fe 2+ generated by dissolving the calcined powder with acid and substituting the eluted Ti 3+ with Fe 3+ with an absorptiometer. is there.
Furthermore, room temperature resistance was measured by a four-terminal method using a digital voltmeter. The rate of change in resistance was calculated by dividing the maximum resistance value from room temperature (25 ° C.) to 250 ° C. by the room temperature resistance value and using the common logarithm.
These measurement results are shown in Table 1.
[0012]
[Table 1]
[0013]
As is clear from the results shown in Table 1, in Examples 1 to 4, the average particle diameter of the calcined powder (barium titanate powder) is 1.0 μm or less and the concentration of Ti 3+ is 0.0003 wt% or more. The Ba / Ti ratio is 1.000 or more and 1.010 or less, and the obtained multilayer semiconductor ceramic electronic component (sample) has a room temperature resistance of 0.2Ω or less and a resistance change rate of 2.7 digits. The above characteristics are obtained.
On the other hand, as in Comparative Example 1, a laminated type manufactured using a barium titanate powder in which Ti 3+ cannot be detected even if the average particle diameter of the barium titanate powder is 0.3 μm and fine particles. For the semiconductor ceramic electronic component (sample), the room temperature resistance is as high as 0.50Ω and the resistance change rate is as low as 2.5 digits.
Further, even when Ti 3+ is sufficiently present in the barium titanate powder as in Comparative Examples 2 and 3, if the average particle diameter of the barium titanate powder exceeds 1.0 μm, the room temperature resistance is high, and the resistance change The rate is also low.
Further, when the Ba / Ti ratio is less than 1.000 or exceeds 1.010 as in Comparative Examples 4 and 5, Ti 3+ is sufficiently present in the barium titanate powder and the average particle size is 1.0 μm or less. Even so, the room temperature resistance is as high as 1Ω or more, and the resistance change rate is as low as 2.2 or less.
[0014]
【The invention's effect】
According to the present invention, it is possible to obtain a semiconductor ceramic that has a low resistance at room temperature and a high rate of change in resistance at the Curie temperature or higher.
Further, by using the semiconductor ceramic powder according to the present invention, a laminated semiconductor ceramic electronic component including a semiconductor ceramic layer having a low resistance at room temperature and a high rate of change in resistance at the Curie temperature or higher is obtained. Therefore, the laminated semiconductor ceramic electronic component according to the present invention can be small and have a low resistance and a high resistance change rate.
[Brief description of the drawings]
FIG. 1 is an illustrative view showing one example of a laminated semiconductor ceramic electronic component according to the present invention.
[Explanation of symbols]
DESCRIPTION OF
Claims (3)
前記半導体セラミック層は、請求項1に記載の半導体セラミック粉末を焼結して形成される、正の抵抗温度特性を有する積層型半導体セラミック電子部品。A multilayer semiconductor ceramic electronic component comprising a plurality of alternately laminated semiconductor ceramic layers and a plurality of internal electrodes,
The multilayer ceramic ceramic electronic component having positive resistance temperature characteristics, wherein the semiconductor ceramic layer is formed by sintering the semiconductor ceramic powder according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000008945A JP4123666B2 (en) | 2000-01-18 | 2000-01-18 | Semiconductor ceramic powder and multilayer semiconductor ceramic electronic parts |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000008945A JP4123666B2 (en) | 2000-01-18 | 2000-01-18 | Semiconductor ceramic powder and multilayer semiconductor ceramic electronic parts |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2001203102A JP2001203102A (en) | 2001-07-27 |
| JP4123666B2 true JP4123666B2 (en) | 2008-07-23 |
Family
ID=18537155
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000008945A Expired - Lifetime JP4123666B2 (en) | 2000-01-18 | 2000-01-18 | Semiconductor ceramic powder and multilayer semiconductor ceramic electronic parts |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4123666B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007034830A1 (en) * | 2005-09-20 | 2007-03-29 | Murata Manufacturing Co., Ltd. | Stacked positive coefficient thermistor |
| EP1939899B1 (en) | 2005-09-20 | 2016-12-21 | Murata Manufacturing Co., Ltd. | Stacked positive coefficient thermistor |
-
2000
- 2000-01-18 JP JP2000008945A patent/JP4123666B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JP2001203102A (en) | 2001-07-27 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5594373B2 (en) | SEMICONDUCTOR CERAMIC AND ITS MANUFACTURING METHOD, MULTILAYER SEMICONDUCTOR CERAMIC CAPACITOR WITH VARISTOR FUNCTION AND ITS MANUFACTURING METHOD | |
| JP3812268B2 (en) | Multilayer semiconductor ceramic element | |
| JP3435607B2 (en) | Non-reducing dielectric porcelain composition | |
| CN102245536A (en) | Semiconductor ceramic and positive temperature coefficient thermistor | |
| JP3039513B2 (en) | Barium titanate powder, semiconductor ceramic, and semiconductor ceramic element | |
| JP2012028568A (en) | Multilayer semiconductor ceramic capacitor with varistor function | |
| JP2005335960A (en) | Dielectric ceramic composition and laminated ceramic capacitor | |
| EP1014391B1 (en) | Monolithic semiconducting ceramic electronic component | |
| JP4123666B2 (en) | Semiconductor ceramic powder and multilayer semiconductor ceramic electronic parts | |
| JP3506056B2 (en) | MULTILAYER SEMICONDUCTOR CERAMIC ELEMENT HAVING POSITIVE RESISTANCE TEMPERATURE CHARACTERISTICS AND METHOD FOR PRODUCING MULTILAYER SEMICONDUCTOR CERAMIC ELEMENT HAVING POSITIVE RESISTANCE TEMPERATURE CHARACTERISTICS | |
| CN112759384B (en) | Use of ceramic composition for thermistor, use of ceramic sintered body for thermistor, and thermistor | |
| JP3498211B2 (en) | Multilayer semiconductor ceramic electronic components | |
| JP4487439B2 (en) | Multilayer semiconductor ceramic element and method for manufacturing the same | |
| JP4111754B2 (en) | Ceramic capacitor, dielectric composition thereof, and method for producing the same | |
| JP4780306B2 (en) | Multilayer thermistor and manufacturing method thereof | |
| JP4888264B2 (en) | Multilayer thermistor and manufacturing method thereof | |
| JP3039511B2 (en) | Semiconductor ceramic and semiconductor ceramic element | |
| JP2952062B2 (en) | Non-reducing dielectric porcelain composition | |
| JP3598177B2 (en) | Voltage non-linear resistor porcelain | |
| JP2583091B2 (en) | Dielectric ceramic composition | |
| JP3385631B2 (en) | Non-reducing dielectric porcelain composition | |
| JP2002274940A (en) | Raw material powder for ceramics, method for manufacturing the same, ceramic and method for manufacturing the same, and method for manufacturing laminated ceramic electronic part | |
| JP3385630B2 (en) | Non-reducing dielectric porcelain composition | |
| JP2952061B2 (en) | Non-reducing dielectric porcelain composition | |
| JP2005158896A (en) | Grain-boundary-insulated semiconductor ceramic and laminated semiconductor capacitor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20050420 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20070907 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20070918 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20071115 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20080415 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20080428 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 Ref document number: 4123666 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110516 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120516 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120516 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130516 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130516 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140516 Year of fee payment: 6 |
|
| EXPY | Cancellation because of completion of term |