JPH0795583B2 - Semiconductor device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device in which impurities formed in a semiconductor are prevented from interdiffusion and a method for manufacturing the same.

2. Description of the Related Art In a conventional semiconductor device, as shown in FIG. 4, one conductivity type impurity layer formed on a semiconductor substrate 21, for example, a semiconductor substrate containing an n-type impurity 22 or a polycrystalline silicon film 24,
When electrically connecting to a semiconductor substrate or a polycrystalline silicon film 25 containing an impurity of a conductivity type opposite to the above, for example, a P-type impurity 23, a gold-side conductor layer 26 of aluminum or the like is used once to prevent the formation of a PN junction. I was going.

When a high-resistance semiconductor containing a low-concentration impurity is used as a resistor, when connected to a low-resistance semiconductor containing a high-concentration impurity, the impurities of the low-resistance semiconductor diffuse to the high-resistance semiconductor side, It was necessary to lengthen the resistor.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention When a polycrystalline silicon film having a different conductivity type is connected through a metal conductor layer as in a conventional example, the metal conductor film is connected to each polycrystalline silicon film. A region is required, which hinders high density. Further, when a metal layer is directly formed on the impurity layer formed on the semiconductor substrate, the metal and the semiconductor are inter-diffused, or when a refractory metal is used as the metal, the impurity ions and the metal are inter-diffused. There is a problem that the characteristics of the layer deteriorate.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention is provided with a configuration of implanting disordered ion for preventing diffusion of the conductivity type impurities into a connection region of a semiconductor having a different conductivity type. It is a thing. In addition, the semiconductor device is provided with a configuration in which impurity ions that prevent mutual diffusion of the semiconductor and conductive impurities in the semiconductor and the metal are implanted into a connection region between the one conductive semiconductor substrate and the metal layer.

Action The present invention, by the above-mentioned configuration, the diffusion prevention impurity ions injected into the connection regions of different conductivity types prevent the diffusion of the conductivity type impurity ions in the semiconductor, so that the semiconductors of different conductivity types are directly connected, Does not cause mutual diffusion of impurities,
It is possible to form an electrically favorable connection. Further, the diffusion preventing impurity ions injected into the connection region of the one conductivity type semiconductor and the metal prevent the mutual diffusion of the impurity in the semiconductor and the metal ion in the same manner as described above and prevent the characteristics from deteriorating between the semiconductor and the metal layer. Allow connection.

Example 1 FIG. 1 shows a schematic structure of a semiconductor device according to an example of the present invention, in which 1 is a semiconductor substrate, 2 and 3 are different conductivity types, for example, 2 is n type and 3 is p type. This is an impurity introduction region into which an impurity exhibiting a conductivity type is introduced. Reference numeral 4 is an insulator film, 5 is a polycrystalline silicon film containing n-type impurities, 6 is a polycrystalline silicon film containing P-type impurities, and 7 is nitrogen ions by ion implantation, for example, 4 × 10 ¹⁶ ions at 1.5 KeV. / cm ²
This is the implanted barrier region. Reference numeral 8 is a low resistance conductor layer such as a refractory metal such as titanium or titanium silicide.

In the semiconductor device having the above structure, mutual diffusion of impurities in the polycrystalline semiconductor film is blocked in the nitrogen ion implantation region, and mutual electrical connection is made through the refractory metal. The relationship between the connection resistance of the refractory metal film and the nitrogen ion implantation amount is shown. As is clear from FIG.
When the penetration amount is 5 × 10 ¹⁶ ions / cm ² or less, the connection resistance hardly increases. Further, in order to prevent the diffusion of impurities, it is preferable that the implantation amount be large. Therefore, in order to prevent the diffusion of impurities and to obtain a good electrical connection, the ion implantation amount is 5 × 10 ¹⁶ ions / cm ² or less.

A second embodiment will be described with reference to FIG. 10 is a one conductivity type semiconductor substrate, 11 is an insulator film, 12 is a low resistance polycrystalline silicon film containing impurities in a high concentration, 13 is a high resistance polycrystalline silicon film containing impurities in a low concentration, and 14 is It is an ion diffusion layer for preventing impurity diffusion.

The purpose of this embodiment is to prevent impurities in the low resistance semiconductor region from diffusing into the low resistance region. In order to achieve the above object, as described above, diffusion preventing ions such as nitrogen or carbon are implanted by ion implantation into the connection region between the high concentration impurity layer and the low concentration impurity layer to form the impurity layers having different concentrations. Is electrically connected and the low-concentration impurity layer is used as a resistance layer. According to the above configuration, unlike the conventional example, the high resistance layer can be formed at a high density without increasing the length of the pattern of the resistance layer.

EFFECTS OF THE INVENTION According to the method of the present invention, semiconductors having different impurity concentrations and semiconductors having different conductivity types can be electrically directly connected to each other, and mutual diffusion of respective impurities can be prevented. A high-density semiconductor device can be formed without affecting the respective impurity concentrations and conductivity types.

[Brief description of drawings]

FIG. 1 is a structural sectional view for explaining a first embodiment of the present invention, FIG. 2 is a structural sectional view for explaining a second embodiment of the present invention, and FIG. 3 is an embodiment of the present invention. FIG. 4 is an electrical characteristic diagram of an example, and FIG. 4 is a structural cross-sectional view for explaining a conventional example. 1 ... Semiconductor substrate, 2 ... Conductive impurity layer, 3 ... Other conductive impurity layer, 7 ... Belia region.

Claims (3)

[Claims] 1. A first conductivity type impurity layer and a second conductivity type impurity layer formed on a semiconductor substrate, and non-conductivity type impurity ions are implanted and the first conductivity type impurity layer and the second layer are formed. A low-concentration non-conductivity type impurity ion implantation layer that is connected to the second conductivity-type impurity layer and prevents mutual diffusion between the first conductivity type impurity layer and the second conductivity type impurity layer; A semiconductor device having a low resistance conductor layer formed on an injection layer. 2. The semiconductor device according to claim 1, wherein the non-conductive type impurity ion is nitrogen and the implantation amount is 5 × 10 ¹⁶ ions / cm ² or less. 3. A first polycrystalline silicon layer having a low concentration of impurities and a second polycrystalline silicon layer having a high concentration of impurities formed on an insulating film, and non-conductive impurity ions are implanted. And an impurity diffusion prevention layer formed between the first polycrystalline silicon layer and a second polycrystalline silicon layer, and the impurity ions injected into the impurity diffusion prevention layer are the first polycrystalline silicon layer. And a semiconductor device having a low concentration such that electrical connection can be made between the second polycrystalline silicon layer and the second polycrystalline silicon layer.