JPS5450277A - Semiconductor device - Google Patents

Abstract

PURPOSE: To form a PN junction in the central part of the circumference of a diffusion window and make the element of normal zener voltage-current characteristics by so forming the window that the corner parts thereof is not included in a P type diffused region.

CONSTITUTION: A P type region 14 is provided in an N epitaxial layer 13, and the opposing sides of the diffusion window of the layer 14 forms an N^- type region 15 through a much larger window 12. The regions 14, 15 diffuse laterally up to positions 11', 12' and zener voltage is determined by the junction near the position E-E'. In this way, the corners F, F' of the diffusion window 12 of the region 15 are positioned more than 15μ outer of the P type region 14. Next, electrode windows are provided in the surface insulation film 16 and metal wiring is applied. With this constitution, the corners of the N type diffusion window are on the outside of the P type region and therefore the effect of crystal defects caused by stress based on the difference in the coefficients of expansion between SiO₂ and Si concentrating at the corners may be eliminated and the normal zener diode current-voltage characteristics obtained

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