JPH02216860A - Semiconductor device - Google Patents

Abstract

PURPOSE:To form a resistor element with a desired resistance value by forming trenches, bending in the depth direction thereof, and adjusting the number of the trenches and the depth of the trenches within a limited surface area. CONSTITUTION:Trenches 3 are formed in a P-type silicon substrate 1. Then, a resist 7 is applied and patterned by photolithographic technique. Next, an impurity is injected by using the resist as a mask (an N-type impurity such as P, As for a P-type silicon substrate, and a P-type impurity such as B for an N-type silicon substrate). Then, the resist is removed annealed to obtain a resistor element.

Description

[Detailed description of the invention] [Industrial use alter ego] The present invention relates to a semiconductor device.

[Conventional technology]

Figure 8 is a surface diagram of a conventional semiconductor resistor, Figure 9 is 'fg8
This is a cross-sectional side view taken along the line (■) in the figure.

In the figure, (11 is a silicon substrate CP type), (xi
is an N-type impurity diffusion region, (41 is an electrode ^, (51 is an electrode B).

Further, FIG. 10 is an explanatory diagram of a conventional semiconductor device, and in the figure, (8) is the distance LAB between the electrodes AB.

Next, the operation will be explained.

In FIG. 10, if the impurity density is constant in the entire region of the impurity diffusion region 12) and the width of the impurity diffusion region (2) is constant, then if the resistance [between the electrodes AB] is RO, then RO-kLAB ( k is a positive constant) ・Il
Therefore, the size of the resistance box is proportional to the distance LAB between the surface electrodes.

Therefore, in order to increase the resistance [, the constant 'l1zk must be increased or the distance @LAB must be increased.

In order to increase k, either narrow the width of the resistance element or
As for lowering the impurity density, impurity book r! t″Ir
Changing only a certain area increases the process flow, making it difficult to adjust the resistance value. I narrows the width, L
AB is also made longer. The method of narrowing the width has limitations in photolithography, and the desired resistance element is generally formed by lengthening the LAB, but a large resistance element must be formed as shown in Figure 8. It will occupy a large surface area.

[Problem to be solved by the invention]

Conventional semiconductor resistors are constructed as shown above, so
Forming high resistance requires a large surface area, and in recent years, the degree of integration of semiconductor integrated circuits has improved, and the transistors and capacitance of integrated circuits have increased.

Although it is necessary to reduce the surface area occupied by each element such as a resistor, there is a problem in that it is necessary to obtain a desired resistance within a certain surface area in order to improve the electrical characteristics of the circuit.

This invention was made to solve the above-mentioned problems, and by forming a deep #I (trench) and bending the resistance element in the depth direction, it is possible to have a desired resistance of one straight line in the same occupied area. The purpose is to obtain a semiconductor device.

[Means for Solving Problem 11] The semiconductor device according to the present invention forms a deep #l (trench) and bends it in the depth direction, thereby forming a resistance having a desired resistance 11it- with a small surface area. It is designed to obtain an element.

[Effect]

By bending the resistance element in the depth direction by forming a deep groove (trench), a semiconductor device having a desired resistance value can be obtained with a small surface area.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a surface view of a resistor element which is an embodiment of the present invention.
The figure is a cross-sectional side view taken along the line ■-■ in Figure 1, and Figure 3 is a P
A sectional view showing a state in which a deep groove (trench) is formed in a mold silicon substrate, Figure 4 is a surface view of Figure 3, and Figure 5 is a surface view of Figure 4 after resist patterning.

First, a deep groove (trench) is formed in a P-type silicon substrate as shown in FIG. Next, a resist is applied and patterned using photolithography (FIG. 5). Next, using a resist as a mask, impurities are implanted into a CP type silicon substrate (for example, N type impurities P, ^S, etc., and for an N type silicon substrate, P type impurities B, etc.). Next, by removing the resist and performing one anneal, the resistor elements shown in FIGS. 1 and 2 are obtained.

Next, the operation will be explained using FIGS. 6 and 10. If the resistance value of the resistance element in Fig. 10 is RQ, then RO-k LAB (k n positive (n constant l()
・111Next, if the distance between the electrodes in this invention in FIG. 6 is equal to that in FIG. 10, and the resistance value at this time is R], then R1=k LAB+2nkL7 (on natural number)
・+21fll, from f21 formula R1> Ro
- (3) From equation (2), by adjusting the depth of depth #I (trench), T, and the number of deep grooves nt, it is possible to obtain a resistive element with a desired resistance gain within a certain area. .

In addition, in the above embodiment, the depth #l (trench) depth LT
Although the case where the depth is constant is shown, the depth may be changed as shown in FIG. If the resistance value in this case is R2, then R2-kLAB + 2k(LTI ” LT2 +
LT3) ... (4) Generally, Rz-kLAB+2k(LTI +LT2'p ・=
・-”LTn) ・・-(5+Of course R2>
Becomes an RO.

〔Effect of the invention〕

As described above, according to the present invention, deep grooves (trenches) and #! 1111(
) wrench) by adjusting the depth of the desired resistance 1
It is possible to obtain a resistive element with [0

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a surface view of a resistance element according to an embodiment of the present invention, FIG. 2 is a cross-sectional side view along n-n line in FIG.
The figure is a cross-sectional view of deep grooves formed in a P-type silicon substrate, Figure 4 is a surface view of Figure 3, Figure 5 is a surface view of Figure @4 after resist patterning, and Figure 6 is a view of the resistor element of the present invention. An explanatory diagram, FIG. 7 is a cross-sectional view of a resistance element according to another embodiment of the present invention,
Figure 8 is a surface view of a conventional resistance element, and Figure 9 is the
-A cross-sectional side view taken along the X-ray, FIG. 10 is an explanatory diagram of a conventional resistance element. In the figure, (l) is a silicon substrate, 12) is an N-type impurity diffusion region, (3) is a deep groove (trench), +41 is electrode A1 (5) is electrode B, 171 is resist, (8)
is the distance between the metal AB, LAB, +91ij, the depth t of the deep groove
, 7, lo+ (Ill Q21 n RC groove ('
) Rsa L'rt t LT21LT3. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] When forming a resistance element using an impurity diffusion region of a semiconductor device, by forming a deep groove (trench), bending it in the depth direction, and adjusting the number and depth of the deep groove within a limited surface area. A semiconductor device characterized in that a resistive element having a desired resistance value is formed.