JP3876411B2 - Insulated gate type semiconductor device manufacturing method and insulated gate type semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing an insulated gate semiconductor device and an insulated gate semiconductor device, and more particularly, to charge trap levels associated with introduction of nitrogen into a gate insulating film and an interface for preventing diffusion of boron and hydrogen. In addition, the present invention relates to an insulated gate semiconductor device manufacturing method and an insulated gate semiconductor device that are characterized by a configuration for suppressing the generation of interface states.
[0002]
[Prior art]
In recent years, in an ultrahigh-speed CMOS-LSI, as the miniaturization of an insulated gate transistor has progressed, the gate insulating film becomes as thin as about 2.5 nm or less in terms of oxide film thickness, and boron (B ), Diffusion of hydrogen (H) or the like to the silicon substrate side is a problem.
[0003]
In order to prevent such diffusion of B and H, in the conventional high-speed CMOS-Logic, in order to suppress entry of boron and hydrogen from the gate side to the channel side and to increase hot carrier resistance, gate insulation An oxynitride film containing several percent of nitrogen in the film or an oxynitride film in which nitrogen is segregated only at the substrate interface is used. These oxynitride films are made of oxide such as NO and N ₂ O. It was formed by nitriding using a gas.
[0004]
[Problems to be solved by the invention]
However, when nitrogen is introduced into the oxide film / silicon interface having a good interface state in the above-described oxynitride film forming process, there is a problem that interface states are generated and interface characteristics are deteriorated.
[0005]
Further, in the above-described oxynitride film formation process, nitriding an oxide film with few defects has a problem that a new charge trap level is generated although it helps to suppress diffusion of boron, hydrogen and the like.
[0006]
In any of these cases, the nitrogen introduced into the interface or gate oxide film does not form a perfect bond with the three silicon atoms, but bonds with oxygen and hydrogen. It is speculated as the cause.
Therefore, there has been a demand for a nitrogen introduction method that does not generate new charge trapping levels and interface levels.
[0007]
Accordingly, an object of the present invention is to improve the hot carrier resistance by suppressing the generation of charge trap levels and interface levels in the gate insulating film due to nitrogen introduced into the gate insulating film and at the interface. To do.
[0008]
[Means for Solving the Problems]
Here, means for solving the problems in the present invention will be described with reference to FIG.
1A to 1D, in order to achieve the above object, the present invention provides a method for manufacturing an insulated gate semiconductor device, wherein the surface of the Si substrate 4 is in an atmosphere containing at least one of hydrogen and deuterium. After forming the SiO ₂ film 5 by oxidizing hydrogen, deuterium, and, by performing heat treatment in an atmosphere containing no oxygen, Si substrate / SiO ₂ film interface 1 to P _b center, P _b -H, and, at the same time introducing the interface defects 10 ¹¹ cm ^-2 or more, including at least one of P _b -D, E 'centers in the SiO ₂ film 5, E'-H, and, E'-D After introduction of the defects in the film 10 ¹⁸ cm ^-3 or more, including at least one of, and having a step of nitriding the Si substrate / SiO ₂ film boundary surface 1 and the SiO ₂ film 5.
[0009]
Thus, prior to the nitriding treatment, Si substrate / SiO ₂ film interface 1, P _b center, P _b centers hydrogen are exemplary forms of Figure 1 dangling bond 2 of Si atoms shown in (a) By introducing an interface defect including at least one of P _b —H terminated with an atom and P _b —D having a P _b center terminated with a deuterium atom, the introduced nitrogen atom interface for 6 to form a complete bond with the dangling bonds 2 and bonded to an oxygen atom 8 and bonded to three Si atoms 3 are in that formed the P _b center as shown in FIG. 1 (b) Defects can be reduced.
The surface density of interface defects to be introduced needs to be about 0.1% or more, that is, about 10 ¹¹ cm ⁻² or more, which is almost the same as the density of nitrogen atoms 6 to be introduced.
[0010]
Further, before the nitriding treatment, in the SiO ₂ film 5, a typical embodiment a is E 'center, E' dangling bonds 7 of Si atoms 3 included in the oxide shown in FIG. 1 (c) is centered It was introduced by introducing defects in the film containing at least one of E′-H terminated with a hydrogen atom and E′-D terminated with a deuterium atom at the E ′ center. Nitrogen atoms 6 combine with dangling bonds 7 constituting the E ′ center as shown in FIG. 1D to form complete bonds with the three Si atoms 3, thereby reducing interface defects. it can.
The atomic density of defects in the film to be inserted needs to be about 0.1% or more, that is, about 10 ¹⁸ cm ⁻³ or more, which is almost the same as the density of nitrogen atoms 6 to be introduced.
[0011]
In order to introduce the interface defects and film defects at the same time, we perform the oxidation in an atmosphere containing at least one of hydrogen or deuterium, rather good by forming the Si-H or Si-D, whereby, Generation of an electron capture level or an interface state accompanying the introduction of nitrogen can be suppressed.
[0012]
Further, hydrogen Si-H or Si-D was formed by oxidation, deuterium, and, by heat treatment in an atmosphere containing no oxygen, securely P _b centers or E 'centers by skipping H or D Can be formed.
[0013]
Further, after the nitriding step, it is desirable to heat treatment at 1050 ° C. or less in an inert gas atmosphere containing no nitrogen, whereby it is possible to reliably replace the defective or Makuchu defects and nitrogen in the film, Accordingly, generation of electron capture levels or interface states can be suppressed.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Here, before describing the embodiment of the present invention, the manufacturing process of Reference Example 1 which is the premise thereof will be described with reference to FIG. 2. In order to simplify the description, the manufacturing process of the gate insulating film will be described. I will explain only.
2A. First, after forming a SiO ₂ film 12 to be a gate insulating film having a thickness of, for example, 10 nm on the surface of the p-type silicon substrate 11 by plasma CVD, ⁶⁰ Co at a substrate temperature of 77K. Is irradiated with an irradiation dose of 1 × 10 ⁷ R (X-rays), for example, to thereby cause an E ′ center 14 having a density of 10 ¹⁸ cm ⁻³ or more in the SiO ₂ film 12. Form.
[0015]
A part of the formed E ′ center 14 is terminated by hydrogen in the process gas to become E′-H.
The density of the E ′ center 14 is about 10 ¹³ cm ⁻³ in the as-grown state, that is, immediately after the SiO ₂ film 12 is formed.
[0016]
In this case, the density of the E ′ center 14 can be measured by an ESR (electron spin resonance) method, and E′-H is not directly detected as an interface state density by the ESR method which is an electrical measurement. It can be detected by the infrared absorption method, and can be measured by the ESR method after removing hydrogen atoms terminating dangling bonds by heat treatment.
[0017]
Next, see FIG. 2B. Rapid thermal nitridation of the p-type silicon substrate 11 in a NH ₃ gas atmosphere of 0.1 to 1 atm under a temperature condition of 700 to 1200 ° C. for 5 to 600 seconds (Rapid Thermal Nitridation). The oxynitride film 16 is formed by nitriding the Si / SiO ₂ interface 15 and the SiO ₂ film 12.
[0018]
In this nitriding treatment step, as described in FIGS. 1C and 1D above, the dangling bond constituting the E ′ center 14 or E′-H and the bond of the introduced nitrogen atom are replaced. Thus, when the nitrogen atoms are bonded to the three Si atoms, the E ′ center 14 or E′—H in the oxynitride film 16 disappears, and the generation of electron capture levels is greatly reduced.
[0019]
Next, RTA (rapid heat treatment) is performed at a temperature of 1050 ° C. or lower, for example, 900 ° C. for 5 to 600 seconds in an atmosphere containing no nitrogen, for example, 1 atmosphere of Ar gas. Thus, the substitution of nitrogen atoms with defects in the film such as the E ′ center 14 or E′—H is reliably performed.
[0020]
Thus, in Reference Example 1 , since defects in the film such as the E ′ center 14 or E′-H are introduced into the SiO ₂ film 12 by γ-ray irradiation prior to the nitriding treatment, As the oxynitride film is formed, the generation of electron trap levels in the gate insulating film is greatly reduced, so that desired gate voltage characteristics can be obtained.
[0021]
Next, with reference to FIG. 3, the manufacturing process of Reference Example 2 which is the premise of the present invention will be described. Here, only the manufacturing process of the gate insulating film will be described for the sake of simplicity.
Refer to FIG. 3A. First, after a SiO ₂ film 12 serving as a gate insulating film having a thickness of, for example, 10 nm is formed on the surface of the p-type silicon substrate 11 by a plasma CVD method, 100 keV is obtained at a substrate temperature of 77K. By irradiating energy X-rays 17, E ′ centers 14 having a density of 10 ¹⁸ cm ⁻³ or more are formed in the SiO ₂ film 12.
Also in this case, a part of the formed E ′ center 14 is terminated by hydrogen in the process gas and becomes E′-H.
[0022]
See FIG. 3B. Next, in the same manner as in Reference Example 1 above, the p-type silicon substrate 11 is placed for 5 to 600 seconds under a temperature condition of 700 ° C. to 1200 ° C. in an NH ₃ gas atmosphere of 0.1 to 1 atm. By performing the rapid thermal nitridation process, the Si / SiO ₂ interface 15 and the SiO ₂ film 12 are nitrided to form an oxynitride film 16.
[0023]
In this nitriding treatment step, as described in FIGS. 1C and 1D above, the dangling bond constituting the E ′ center 14 or E′-H and the bond of the introduced nitrogen atom are replaced. Thus, when the nitrogen atoms are bonded to the three Si atoms, the E ′ center 14 or E′—H in the oxynitride film 16 disappears, and the generation of electron capture levels is greatly reduced.
[0024]
Next, as in Reference Example 1 above, in an atmosphere containing no nitrogen, for example, an Ar gas atmosphere of 1 atm, at a temperature of 1050 ° C. or lower, for example, 900 ° C. for 5 to 600 seconds. By performing RTA (rapid heat treatment), defects in the film such as E ′ center 14 or E′—H and nitrogen atoms are surely replaced.
[0025]
Thus, in Reference Example 2 , since defects in the film such as E ′ center 14 or E′-H are introduced into the SiO ₂ film 12 by X-ray irradiation prior to the nitriding treatment, as in the prior art. As the oxynitride film is formed, the generation of electron trap levels in the gate insulating film is greatly reduced, so that desired gate voltage characteristics can be obtained.
[0026]
Next, with reference to FIG. 4, the manufacturing process of Reference Example 3 which is the premise of the present invention will be described. Here, only the manufacturing process of the gate insulating film will be described for the sake of simplicity.
4A. First, after forming a SiO ₂ film 12 to be a gate insulating film having a thickness of, for example, 10 nm on the surface of the p-type silicon substrate 11 by a plasma CVD method, Si ions 18 are ion-implanted. it allows to the Si / SiO ₂ interface 15 to form a P _b centers 19 of 10 ¹¹ cm ^-2 or more areal density.
[0027]
Also in this case, a part of the formed P _b center 19 is terminated by hydrogen in the process gas to become P _b -H.
The density of P _b centers 19 of the case can be measured by the ESR method, also, P _b -H is in electrical measurements in which the ESR method is not detected directly as interface state density, and an infrared absorption method, It can be measured by the ESR method after removing hydrogen atoms terminating dangling bonds by heat treatment.
[0028]
In the as-grown state, that is, immediately after the SiO ₂ film 12 is formed, the interface state density is about 5 × 10 ¹⁰ cm ⁻² , and the density of the _Pb center 19 is 1/10. the following although 5 × 10 ⁹ cm ^-2 or less, when exposed for 2 minutes in atomic hydrogen atmosphere, 2 × ¹⁰ 10 cm ^-2 order of P _b centers 19 are formed.
[0029]
Next, as in Reference Example 1 above, the p-type silicon substrate 11 is placed in the NH ₃ gas atmosphere at 0.1 to 1 atm for 700 seconds to 1200 ° C. for 5 to 600 seconds. By performing the rapid thermal nitridation process, the Si / SiO ₂ interface 15 and the SiO ₂ film 12 are nitrided to form an oxynitride film 16.
[0030]
In this nitriding process, as described in the above FIG. 1 (a) and (b), and the bond of the nitrogen atoms introduced as dangling bonds constituting the P _b center 19 or P _b -H substituted Te, along with P _b center 19 or P _b -H in the Si / SiO ₂ interface 15 disappears by the nitrogen atom is bonded to three Si atoms, the occurrence of interface states is greatly reduced.
[0031]
Next, as in Reference Example 1 above, in an atmosphere not containing nitrogen, for example, in an Ar gas atmosphere of 1 atm, at a temperature of 1050 ° C. or lower, for example, 900 ° C. for 5 to 600 seconds. by performing RTA (rapid thermal processing), ensure the replacement of P _b center 19 or P _b -H interface defects and nitrogen atoms, such as.
[0032]
Thus, in Reference Example 3, to the Si / SiO ₂ interface 15 by ion implantation prior to the nitriding treatment P _b center 19 or P _b -H etc. because it introduces interfacial defects, as in the prior art, As the oxynitride film is formed, the generation of interface states at the Si / SiO ₂ interface 15 is greatly reduced, so that the desired gate voltage characteristics can be obtained.
[0033]
Next, with reference to FIG. 5, the manufacturing process of Reference Example 4 which is the premise of the present invention will be described. Here, in order to simplify the description, only the manufacturing process of the gate insulating film will be described.
Refer to FIG. 5A. First, after forming a SiO ₂ film 12 to be a gate insulating film having a thickness of, for example, 10 nm on the surface of the p-type silicon substrate 11 by plasma CVD, the hydrogen plasma 20 is subjected to 1 minute. by exposing above, the Si / SiO ₂ interface 15 to form a P _b centers 19 of 10 ¹¹ cm ^-2 or more areal density.
Also in this case, a part of the formed P _b center 19 is terminated by hydrogen in the process gas to become P _b -H.
[0034]
Next, refer to FIG. 5B. As in Reference Example 1 , the p-type silicon substrate 11 is placed for 5 to 600 seconds in an NH ₃ gas atmosphere of 0.1 to 1 atm under a temperature condition of 700 ° C. to 1200 ° C. By performing the rapid thermal nitridation process, the Si / SiO ₂ interface 15 and the SiO ₂ film 12 are nitrided to form an oxynitride film 16.
[0035]
In this nitriding process, P _b center 19 or P _b -H and bond dangling bonds and introduced nitrogen atoms constituting the substituted a, Si / SiO by the nitrogen atom is bonded to three Si atoms with _two interfaces 15 P _b center 19 or P _b -H disappears, the occurrence of interface states is greatly reduced.
[0036]
Next, as in Reference Example 1 above, in an atmosphere containing no nitrogen, for example, an Ar gas atmosphere of 1 atm, at a temperature of 1050 ° C. or lower, for example, 900 ° C. for 5 to 600 seconds. by performing RTA (rapid thermal processing), ensure the replacement of P _b center 19 or P _b -H interface defects and nitrogen atoms, such as.
[0037]
Thus, in Reference Example 4, to the Si / SiO ₂ interface 15 by the hydrogen plasma treatment prior to nitriding treatment P _b center 19 or P _b -H etc. because it introduces interfacial defects, as in the prior art As the oxynitride film is formed, the generation of interface states at the Si / SiO ₂ interface 15 is greatly reduced, so that the desired gate voltage characteristics can be obtained.
[0038]
Based on the above, the manufacturing process of the first embodiment of the present invention will be described next with reference to FIG. 6. Here, in order to simplify the description, only the manufacturing process of the gate insulating film will be described. explain. 6A. First, the p-type silicon substrate 11 is oxidized at, for example, 800 ° C. in an oxidizing atmosphere 21 having a hydrogen partial pressure of 0.5 atm. On the surface, a SiO ₂ film 22 is formed which becomes a gate insulating film having a thickness of 10 nm, for example.
[0039]
In this oxidation treatment step, Si—H 24 is formed in the Si / SiO ₂ interface 23 and the SiO ₂ film 22. The total density of the E ′ center 14 and the _Pb center 19 described later is 10 in terms of surface density. Adjust the oxidation treatment time to ¹¹ cm ^-2 .
[0040]
Next, refer to FIG. 6B. By performing heat treatment in a N ₂ gas atmosphere 25 containing no H, D, O at a temperature of 450 ° C. to 600 ° C., the Si / SiO ₂ interface 23 and the SiO ₂ film 22 are treated. The hydrogen atoms of Si—H 24 therein are blown to form the E ′ center 14 and the P _b center 19.
[0041]
See FIG. 6C. Next, in the same manner as in Reference Example 1 above, the p-type silicon substrate 11 is placed for 5 to 600 seconds under a temperature condition of 700 to 1200 ° C. in an NH ₃ gas atmosphere of 0.1 to 1 atm. By performing the rapid thermal nitriding process, the Si / SiO ₂ interface 23 and the SiO ₂ film 22 are nitrided to form an oxynitride film 26.
[0042]
In this nitriding process, by replacing a bond of P _b centers 19 or P _b -H constituting the dangling bonds or E 'center 14 or a nitrogen atom introduced with dangling bonds constituting the E'-H is , with P _b center 19 or P _b -H and acid E 'center 14 or E'-H nitride film 26 of the Si / SiO ₂ interface 23 disappears by the nitrogen atom is bonded to three Si atoms, The generation of interface states and electron capture centers is greatly reduced.
[0043]
Next, as in Reference Example 1 above, in an atmosphere not containing nitrogen, for example, in an Ar gas atmosphere of 1 atm, at a temperature of 1050 ° C. or lower, for example, 900 ° C. for 5 to 600 seconds. By performing RTA (rapid heat treatment), interfacial defects such as P _b center 19 or P _b —H and defects in the film such as E ′ center 14 or E′—H and nitrogen atoms are surely replaced.
[0044]
Thus, in the first embodiment of the present invention, since the oxidation treatment in the hydrogen-containing oxidizing atmosphere prior to the nitriding treatment, to the Si / SiO ₂ interface 23 P _b center 19 or P _b - Since interfacial defects such as H are introduced and defects in the film such as E ′ center 14 or E′-H are introduced into the SiO ₂ film 22, with the formation of the oxynitride film as in the prior art, Since the generation of the interface state at the Si / SiO ₂ interface 23 and the generation of the electron capture level in the gate insulating film are greatly reduced, the desired gate voltage characteristics can be obtained.
[0045]
Having thus described the implementation of the embodiment of the present invention, the present invention is not limited to the configuration described in the form of implementation, it can be variously modified in the.
For example, in the form of implementation described above, is performed nitrided with NH ₃ in an atmosphere containing NH _3, it is not limited to NH ₃ atmosphere containing NO atmosphere or N ₂ O containing NO N _{A 2} O atmosphere may be used.
[0046]
Further, in the implementation described above is performed an oxidation treatment in the hydrogen-containing oxidizing atmosphere is, for example, deuterium partial pressure of performing oxidation treatment in deuterium-containing oxidizing atmosphere 0.5 atm even better, in this case, along with P _b center, P _b -D is formed.
[0047]
Here, the detailed features of the present invention will be described again with reference to FIG.
1A to 1D (Appendix 1) After oxidizing the surface of the Si substrate in an atmosphere containing at least one of hydrogen and deuterium to form a SiO ₂ film, hydrogen, deuterium, and oxygen by performing the heat treatment in an atmosphere not containing the Si substrate / SiO ₂ film interface P _b center, P _b -H, and, P _b -D 10 ¹¹ cm interfacial defects including at least one of At the same time as introducing ⁻² or more, after introducing a defect in the film containing at least one of E ′ center, E′-H, and E′-D into the SiO ₂ film by 10 ¹⁸ cm ⁻³ or more, A method of manufacturing an insulated gate semiconductor device, comprising: nitriding the Si substrate / SiO ₂ film interface and the SiO ₂ film.
(Supplementary Note 2) The after nitriding step, the manufacturing method according to Supplementary Note 1 Symbol placement of an insulated gate semiconductor device characterized by having a step of heat treatment at 1050 ° C. or less in an inert gas atmosphere containing no nitrogen.
(Appendix 3 ) An insulated gate semiconductor device manufactured by the method for manufacturing an insulated gate semiconductor device according to appendix 1 or 2 .
[0048]
【The invention's effect】
According to the present invention, prior to the nitriding treatment, defects are introduced into the Si / SiO ₂ interface and the SiO ₂ film to form the interface having many defects and the SiO ₂ film. The trap level density is improved to about 1/10, thereby ensuring the boron, hydrogen desorption resistance, and hot carrier resistance of the gate oxynitride film, while maintaining the interface state density and the charge trap level density in the film. A gate oxynitride film with a small amount is realized, which contributes greatly to improving the reliability of an ultra-high integration insulated gate semiconductor device.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a basic configuration of the present invention.
FIG. 2 is an explanatory diagram of a manufacturing process of Reference Example 1 which is a premise of the present invention.
FIG. 3 is an explanatory diagram of a production process of Reference Example 2 , which is a premise of the present invention.
FIG. 4 is an explanatory diagram of a production process of Reference Example 3 , which is a premise of the present invention.
FIG. 5 is an explanatory diagram of a production process of Reference Example 4 which is a premise of the present invention.
FIG. 6 is an explanatory diagram of the manufacturing process of the first embodiment of the present invention.
[Explanation of symbols]
1 Si substrate / SiO ₂ film interface 2 Dangling bond 3 Si atom 4 Si substrate 5 SiO ₂ film 6 Nitrogen atom 7 Dangling bond 8 Oxygen atom 11 P-type silicon substrate 12 SiO ₂ film 13 γ-ray 14 E ′ center 15 Si / SiO ₂ interface 16 Oxynitride film 17 X-ray 18 Si ion 19 _Pb center 20 Hydrogen plasma 21 Oxidizing atmosphere 22 SiO ₂ film 23 Si / SiO ₂ interface 24 Si-H
25 N ₂ gas atmosphere 26 Oxynitride film

Claims (2)

By oxidizing the surface of the Si substrate in an atmosphere containing at least one of hydrogen and deuterium to form a SiO ₂ film, heat treatment is performed in an atmosphere that does not contain hydrogen, deuterium, and oxygen. substrate / SiO ₂ film interface P _b center, P _b -H, and, at the same time introducing the interface defects 10 ¹¹ cm ^-2 or more, including at least one of P _b -D, in the SiO ₂ film E 'center, E'-H, and, after introducing at least a film defects including one 10 ¹⁸ cm ^-3 or more of the E'-D, the Si substrate / SiO ₂ film boundary surface and the SiO ₂ A method for manufacturing an insulated gate semiconductor device, comprising: nitriding a film.   An insulated gate semiconductor device manufactured by the method for manufacturing an insulated gate semiconductor device according to claim 1.

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