JPH05198749A - Semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a resistor element having small dependency of a resistance value upon a potential difference by arranging a plurality of forward and reverse diodes in series in an opposite direction in polycrystalline silicon. CONSTITUTION:A reverse diode is formed of a voltage leading N-type impurity layer 4 and a P-type impurity layer 5, a forward diode is further formed of the layer 5 and an N-type impurity layer 9, and one resistor element is formed of the two diodes. One resistor element is formed of the layer 9 and a P-type impurity layer 12, the layer 12 and an N-type impurity layer 10. One resistor element is further formed of the layer 10 and a P-type impurity layer 13, the layer 13 and the layer 4, and the three resistor elements are formed in series. Thus, a resistance value obtained by the elements becomes three times as large as a conventional resistance value, and voltage dependency upon an applied voltage can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly to a resistance element formed of a polycrystalline silicon layer.

[0002]

2. Description of the Related Art FIG. 5 shows a structural cross-sectional view of a conventional resistance element using polycrystalline silicon formed on a semiconductor substrate.

In FIG. 5, a silicon oxide film 2 is formed on a semiconductor substrate 1, both ends of which are composed of N-type impurity layers 4 for voltage extraction, and N-type impurity layers for voltage extraction are formed. Regions other than 4 are formed of the P-type impurity layer (a) 5, and a conventional resistance element in which an aluminum wiring 7 is formed via an interlayer insulating film 6 deposited on the upper portion is shown.

The resistance element shown in FIG. 4 controls a current flowing between two terminals by a potential difference applied to the aluminum wiring 7 and is used as a resistance. The above-described current flowing between the two terminals is limited by the reverse current flowing through the junction between the N-type impurity layer 4 and the P-type impurity layer (a) 5 in the voltage drawing portion.

The curve (B) in FIG. 4 shows the dependence of the conventional resistance value on the basis of the potential difference, with the potential difference applied to the aluminum wiring 7 on the horizontal axis and the resistance value at that time on the vertical axis. It is a thing.

[0006]

In the conventional resistance element, as shown by the curve (B) in FIG. 4, the resistance value greatly depends on the potential difference. For example, when a conventional resistance element is used in a potential difference of 0 to 5V, a resistance value near 0V and 5V
There is a problem that the resistance value in the vicinity varies greatly and it is difficult to obtain a constant resistance value in a wide range of voltage.

Therefore, the present invention is intended to solve such a problem, and an object thereof is to provide a resistance element in which the resistance value is less dependent on the potential difference.

[0008]

The semiconductor device of the present invention comprises:
In a semiconductor device having a resistance element made of a polycrystalline silicon layer in which a second conductivity type region is formed on both sides of a first conductivity type region, a forward diode and a reverse diode are opposed to each other in the polycrystalline silicon. It is characterized in that a plurality of them are arranged in series.

[0009]

1 is a structural sectional view of a resistance element of the present invention using polycrystalline silicon formed on a semiconductor substrate.

In FIG. 1, a silicon oxide film 2 is formed on a semiconductor substrate 1, and both ends of the silicon oxide film 2 are N-type impurity layers 4 for extracting voltage, except for the N-type impurity layer 4 for extracting voltage. The region of N-type impurity layer (a) 9, N-type impurity layer (b) 10, P-type impurity layer (a) 5, P-type impurity layer (b) 12 and P-type impurity layer (c) 13 A resistance element of the present embodiment is shown which is formed of polycrystalline silicon configured and further has an aluminum wiring 7 formed on the upper part thereof with an interlayer insulating film 6 interposed therebetween.

FIG. 2 shows an equivalent circuit of the resistance element of this embodiment. The resistance element of the present embodiment is a conventional resistance element in which a forward diode and a reverse diode are combined,
Three are connected in series. Referring to FIG. 1, an N-type impurity layer 4 for extracting voltage and a P-type impurity layer (a) 5 form a reverse diode, and P
The type impurity layer (a) 5 and the N type impurity layer (a) 9 form a forward diode, and these two diodes form one resistance element. Similarly, the N-type impurity layer (a) 9 and P
One resistance element is formed by the type impurity layer (b) 12, the P type impurity layer (b) 12 and the N type impurity layer (b) 10, and the N type impurity layer (b) 10 and P The type impurity layer (c) 13, the P-type impurity layer (c) 13 and the voltage-drawing N-type impurity layer 4 form one resistance element, and the above three resistance elements are formed in series.

Therefore, the resistance value obtained by the resistance element of this embodiment is three times as large as the resistance value at a voltage which is one third of the applied voltage applied to the conventional resistance element. The curve (A) in FIG. 4 shows the dependence of the resistance value of this embodiment on the potential difference, in which the horizontal axis represents the potential difference applied to the aluminum wiring 7 and the vertical axis represents the resistance value at that time. Is.

As shown by the curve (A) in FIG. 4, the resistance value of the resistance element according to the present invention has less voltage dependency due to the applied voltage than that of the conventional resistance element.

Next, one embodiment of a method for manufacturing a semiconductor device of the present invention will be described with reference to FIGS. 3 (a) to 3 (f).

FIG. 3A shows a semiconductor substrate 1 having about 100 layers.
After forming about 1000∂ of polycrystalline silicon 3 on the 0Å deposited silicon oxide film 2, the above-mentioned silicon oxide film 3 is formed.
Is a pattern.

In FIG. 3B, patterning is performed by photolithography, and boron ions are used at 5 × 10 ¹³ to 1 × 10 ¹⁴ at about 20 kev using the resist mask 8 as a mask.
P-type impurity layer is formed on the polycrystalline silicon layer 3 by implanting / cm ² therein.

FIG. 3C shows the above-mentioned polycrystalline silicon layer 3
Patterning is performed thereon by photolithography and the resist film 8 is used as a mask, and an N-type impurity layer 4 for voltage extraction and an N-type impurity layer for voltage extraction are provided at both ends of the polycrystalline silicon layer 3.
The N-type impurity layer (a) 9 and the N-type impurity layer (b) 10 are formed in a region other than the type impurity layer 4 and arsenic ions are set at about 60 kev.
It is formed by implanting × 10 ^{15 to} 5 × 10 ¹⁵ / cm ² . In the figure, P-type impurity layers (a) 5, P
The type impurity layer (b) 12 and the P type impurity layer (c) 13 are regions of the polycrystalline silicon 3 in which the N type impurity is not implanted among the P type impurity regions implanted in the previous process.

FIG. 3 (d) shows that a silicon oxide film is formed as an interlayer insulating film 6 by chemical vapor deposition to form about 3000 Å, and then it is used as a lead electrode of the present resistance element on the interlayer insulating film 6 described above. The structure of this embodiment obtained by forming the aluminum wiring 7 is shown.

In this embodiment, the N-type impurity layer is used for the first conductive layer and the P-type impurity layer is used for the second conductive layer. It is also applicable when using an impurity layer.

[0020]

The resistance element according to the present invention has a structure in which a plurality of forward diodes and opposite diodes are connected to each other, so that the resistance value is less likely to change due to the potential difference between the two terminals. Get a resistance element. This has a great effect that the range of use of the conventional resistance element, which has been limited by design because of its strong voltage dependency, is expanded.

[Brief description of drawings]

FIG. 1 is a diagram showing a structural cross-sectional view of a semiconductor device of the present invention.

FIG. 2 is a diagram showing an equivalent circuit of a resistance element of the present embodiment.

3A to 3D are diagrams showing an embodiment of a method for manufacturing a semiconductor device of the present invention.

FIG. 4 is a diagram showing voltage dependence of resistance value. A curve (A) is a diagram showing the potential difference dependency of the resistance value in the conventional resistance element. A curve (B) is a diagram showing the potential difference dependence of the resistance value in the resistance element of the present invention.

FIG. 5 is a diagram showing a structural cross-sectional view of a conventional semiconductor device.

[Explanation of symbols]

 1 semiconductor substrate 2 silicon oxide film 3 polycrystalline silicon layer 4 N-type impurity layer for voltage extraction 5 P-type impurity layer (a) 6 interlayer insulating film 7 aluminum wiring 8 resist film 9 N-type impurity layer (a) 10 N-type impurity Layer (b) 12P-type impurity layer (b) 13P-type impurity layer (c)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location H01L 29/91 7735-4M H01L 21/88 N 8225-4M 29/91 K

Claims (1)

[Claims] 1. A semiconductor device comprising a resistance element made of a polycrystalline silicon layer in which a second conductivity type region is formed on both sides of a first conductivity type region, wherein a forward diode and a reverse diode are provided in the polycrystalline silicon. A plurality of semiconductor devices are arranged in series in opposite directions.