JPS5457981A - Semiconductor device - Google Patents

Abstract

PURPOSE:To establish the resistive element less in voltage dependancy, by providing the diffusion resistance layer in the separation epitaxial layer formed on the semiconductor substrate, forming an electrode bridging the epitaxial layer at the both ends, and forming the parallel resistance with the epitaxial layer and the resistive layer. CONSTITUTION:The N type layer 33 is epitaxially grown on the P type Si substrate 31, P type impurity is diffused on a given region of the surface, and the P type isolation region 35 is formed, which reaches the substrate 31. In a part of 33-1 of the layer 33 isolated like this, P type region 34 is formed by diffusion and the electrodes E and P bridging the region 33-1 are fixed at the both ends and the distance is used for the diffusion resistance. A voltage is applied between the electrodes E and P and the magnitude is changed, then since the both regions are electrically connected between the region 33-1 and the region 34, no depletion layer can be spread. But, although the width of depletion layer D is varied between the region 33-1 and the substrate 31 and the resistance value is changed, since the layer resistance is great, the variation due to the voltage of the parallel resistance consisting of the region 35-1 and the region 34 is less.