JPH043462A - Semiconductor resistance element - Google Patents

Abstract

PURPOSE:To reduce the occupying area of a resistance element and to reduce in size a device by providing two or more selectively diffused regions, crossing and coupling them by lateral diffusing at the time of diffusing, and forming an integral resistor. CONSTITUTION:After an insulating film 2 is formed on an N-type semiconductor substrate 1, diffusing windows 3A, 3B are opened, for example, at an interval 4 of 4-6mum, it is etched, and an impurity is diffused. Then, two diffused regions 5A, 5B are crossed at the center of the interval 4 by the lateral diffusion. the crossed region is a region where laterally diffused at the outside from the positions of the windows 3A, 3B in a diffusion profile and concentration is considerably reduced. The adjacent intervals 4 between the plurality of separated windows 3A, 3B are suitably provided to couple the adjacent diffused regions by the lateral diffusion at the time of diffusing. Since the coupled part is disposed at the end of diffusing, an impurity concentration is low. Accordingly, if the diffused regions 5A, 5B formed integrally are used as resistors, this parts become high resistance.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to semiconductor resistance elements, particularly high resistance elements.

[Prior Art 1] A semiconductor resistance element uses, as a resistor, a diffusion region in which an impurity of the opposite conductivity type is diffused into a negative conductivity type semiconductor substrate, and an electrode terminal is provided in this diffusion region to form a semiconductor resistance element. Here, the semiconductor substrate is a substrate including an epitaxial layer.

Figures 5 and 6 are plan views showing one example, and C-C
FIG. After selectively diffusing P-type impurities into the N-type semiconductor substrate 1 to form a diffusion region 5 with a layer resistance of 200 to 300 Ω/hole, an electrode 7 is provided in the contact hole 6 formed in the newly formed insulating film 2'. There is. This electrode 7 becomes a resistance terminal. In addition, in the figure, 3 indicates a pattern boundary of a diffusion window when forming the diffusion region 5.

[Problem to be Solved by the Invention 1] Since the above-mentioned resistance element uses a diffusion region by selective diffusion as a resistor, its layer resistance is limited to only a limited region of 200 to 300 Ω/hole due to the concentration profile of diffusion. Can not be removes. Therefore, in order to obtain a high resistance element, the resistance width must be reduced or the resistance length must be increased. However, due to manufacturing reasons, the resistance width is limited to a minimum of about 5 μm, and the length is increased within this width.As a result, in semiconductor devices that require a large number of high-resistance elements,
The disadvantage is that the area required is inevitably large due to the area occupied by the resistive element.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and provide a high-resistance semiconductor resistance element that occupies a small area.

1. Means for Solving the Problem] A semiconductor resistance element according to the present invention uses a diffusion region formed on a semiconductor substrate by selective diffusion as a resistor, and this diffusion region is formed on an insulating film on the semiconductor substrate. Each diffusion region generated by diffusion from a plurality of diffusion windows formed separately from each other is integrally formed by combining with each adjacent diffusion region by lateral diffusion during diffusion.

[Function] By appropriately setting adjacent intervals between the plurality of separated diffusion windows, adjacent diffusion regions can be connected to each other by lateral diffusion during diffusion. The connecting part is
Since it is at the diffusion tip, the impurity concentration is low. Therefore, if the integrally formed diffusion region is used as a resistor, this portion will have a high resistance component.

[Examples] Examples of the present invention will be described below with reference to the drawings. Fig. 1 is a plan view of the first embodiment, and Fig. 2 is A-A in Fig. 1.
It is an A sectional view. After forming the insulating film 2 on the N-type semiconductor substrate 1, the two rectangular diffusion windows 3A and 3B are spaced 4 to 4.
Formed by etching with a gap of 6 μm. Then, when the P-type impurity is diffused, two diffusion regions 5A,
5B intersect approximately at the center of interval 4 due to lateral diffusion. This intersection can be achieved by setting the distance 4 to be less than twice the depth from the surface of the diffusion bond. This intersection region is a region that is laterally diffused outward from the positions of the diffusion windows 3A and 3B, and is a region where the concentration is considerably reduced in the diffusion profile, so it is a diffusion region 5A.

When 5B is formed with a resistance of 200 to 30Ω/hole, the layer resistance of this portion locally becomes about 2Ω to IOKΩ/hole.

The two diffusion regions 5A and 5B are combined to form an integral diffusion region, and as shown in the figure, a contact 86 is provided in the newly formed insulating film 2', and an electrode 7 is formed by patterning in this portion.

The resistance value between the two electrodes 7 is such that the crossing region 8 becomes a high resistance part in the resistor, and a high resistance can be obtained as a resistor even if the distance between the outer ends of the diffusion windows 3A and 3B is not very long. be able to.

In the above embodiment, there is one intersection region 8, but this number can be made into a plurality. As a second embodiment, an example in which three diffusion windows are provided and the number of intersection regions is two is shown in FIGS. 3 and 4. Figure 3 is its plan view, Figure 4 is B of Figure 3.
-B sectional view. Two crossing regions 8 are connected in series,
-A much higher resistance value can be obtained.

[Effects of the Invention] As explained above, in a semiconductor resistance element in which a resistor is a diffusion region formed by selective diffusion, two or more selective diffusion regions are provided, and the distance between adjacent diffusion regions is reduced by lateral diffusion during diffusion. The resistors are crossed and connected to form an integrated resistor.

This joint has high resistance. Therefore, since the above-mentioned high-resistance coupling portion is included between the electrodes of the semiconductor resistance element, high resistance can be easily obtained without requiring a very large distance between the electrodes. As a result, in a semiconductor device including a large number of high resistance elements, the area occupied by the resistance elements can be reduced and the size of the device can be reduced.

[Brief explanation of drawings]

1 and 2 are a plan view and a sectional view of the first embodiment of the present invention, FIGS. 3 and 4 are a plan view and a sectional view of the second embodiment, and FIGS. 5 and 6 1 is a plan view and a sectional view of a conventional example. l...Semiconductor substrate, 2-...Insulating film, 3A,
3B-- Diffusion window, 4... (3A. Interval between 3B), 5A. B...diffusion region, 7...electrode, 8...crossing portion. Patent applicant Yamagata NEC Co., Ltd.

Claims (1)

[Claims] In a semiconductor resistance element that uses, as a resistor, a diffusion region formed by diffusing an impurity of a conductivity type different from the conductivity type on a semiconductor substrate of one conductivity type, the elements are formed separately from each other in an insulating film on the semiconductor substrate. , each diffusion region generated by diffusion from a plurality of diffusion windows is integrally formed by combining with each adjacent diffusion region by lateral diffusion during diffusion, and this integrally formed diffusion region is A semiconductor resistance element characterized by being used as a resistor.