JPS61216356A - Semiconductor resistor - Google Patents

Abstract

PURPOSE:To realize with excellent reproducibility a semiconductor resistor having a correct resistance value by a method wherein the structure of an electrode lead-out region is constructed of two layers of a resistive element and the silicide which is a reaction product of metal and silicon. CONSTITUTION:Silicide 4a and 4b are formed respectively in the opposite ends separated by a mask 5 on the surface of a resistive element 3 formed of polycrystalline silicon. The silicides 4a and 4b constitute resistant regions for leading out electrodes, and they are formed in such a manner that a metal film of tungsten, platinum, titanium or the like is made to grow on the surface of the resistive element 3 with a mask layer 5 of silicon nitride, for instance, used as a mask and thereafter heat treatment is applied thereto so that a reaction produce of said metal and polycrystalline silicon is made to grow thereon. The silicides 4a and 4b thus formed show a layer resistance lower by one or several figures in general than polycrystalline silicon.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor resistor whose resistor is single crystal silicon or polycrystalline silicon containing impurities.

[Conventional technology]

FIG. 3 shows a conventional semiconductor resistor using polycrystalline silicon as a resistor. In FIG. 3, 1 is a semiconductor substrate, 2 is a thick field insulating film, 3 is a resistor made of polycrystalline silicon,
3a and 3b are low resistance regions provided at both ends of the resistor 30, and 5 is a mask layer for forming the low resistance regions 3g and 3b, which is made of silicon nitride, for example.

[Problem that the invention seeks to solve]

Generally, a relatively low concentration of impurity such as phosphorus or arsenic is ion-implanted into the resistor 3 to determine its resistance value, and the low resistance regions aa and ab used as extraction electrodes are
A high concentration of phosphorus or arsenic is introduced by thermal diffusion or ion implantation using the mask layer 5, but since the impurity diffuses very quickly into the polycrystalline silicon, as shown in FIG. As shown in FIG. 2, impurities in the low resistance region diffused into the resistor 3 over several microns, shortening the length 8 of the resistor 3 and deteriorating reproducibility. Moreover, for this reason, the dimensions of the resistor itself have also increased because it is necessary to provide a margin of 70 minutes for the diffusion of high concentration impurities in the lateral direction.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a structure in which the electrode lead-out region of a single-crystal semiconductor or polycrystalline silicon resistor is formed by a reaction between the resistor, metal, and silicon. It has a two-layer structure with silicide.

〔Example〕

Next, the present invention will be explained by examples.

FIG. 1 is a sectional view of an embodiment of the present invention. In the figure, l is a semiconductor substrate, 2 is a thick field insulating film, and 3 is a resistor made of polycrystalline silicon.
The 0 silicides 4a and 4b in which b are formed respectively form low resistance regions for leading out electrodes. For example, using the silicon nitride mask layer 5 as a mask, tungsten, platinum, titanium, etc. are applied to the surface of the resistor 3. After growing a metal film, a heat treatment is performed to grow a reaction product between these metals and polycrystalline silicon, which is formed by K and generally exhibits a layer resistance that is orders of magnitude or several orders of magnitude lower than that of polycrystalline silicon. .

Crystalides 4a and 4b can also be formed directly on the surface of polycrystalline silicon 3 by a method such as sputtering.

FIG. 2 is a sectional view of another embodiment of the invention.

In the figure, l is a semiconductor substrate, 12 is a thick field insulating film, 13 is a single-crystal silicon resistor layer having a PN junction with the semiconductor substrate l, and the surfaces on both sides of the resistor layer 13 separated by a mask 5 are , silicide layers 6a and 6b are provided to form extraction electrodes.

〔Effect of the invention〕

In the semiconductor resistor of the present invention, since the silicide in the low resistance region for leading out the electrodes does not seep into the lower part of the mask, the resistance value can be determined accurately based on the dimensions of one mask, and therefore the correct resistance value can be determined. Semiconductor resistance can be realized with good reproducibility. In addition, since there is no need to allow for unnecessary margins in the overall size of the resistor, it can be formed compactly, and only one resistor can be used for high integration.

[Brief explanation of drawings]

FIG. 1 is a sectional view of one embodiment of the present invention, FIG. 2 is a sectional view of another embodiment of the invention, and FIG. 3 is a sectional view of a conventional semiconductor resistor. 1.11... Semiconductor substrate, 2,12...
・Thick field insulating film, 3... Polycrystalline silicon resistor, 4a, 4b, 6m, 6b... Silicide, 5... Mask, 7... Lateral diffusion area, 8... Resistor dimensions. Figure 3

Claims (1)

[Claims] A semiconductor resistor using a single crystal semiconductor or polycrystalline silicon as a resistor, characterized in that the surface of the connection region provided at both ends of the resistor has silicide, which is a reaction product of metal and silicon. A semiconductor resistor.