Semiconductor device and method for producing the same

Abstract

Provided are a semiconductor device having a high breakdown voltage and attaining the restraint of the action of a parasite bipolar transistor, and a method for producing the device. A high-breakdown-voltage p-channel-type transistor included in the semiconductor device has a first n-type semiconductor layer arranged in a semiconductor substrate and at a main-surface-side (upside) of a p-type region in the semiconductor substrate, and a local n-type buried region arranged just below a first p-type dopant region to contact the first n-type semiconductor layer.

What is claimed is: 
     
         1 . A method for producing a semiconductor device comprising a semiconductor substrate having a main surface and further having, in an internal region thereof, a p-type region, and a high-breakdown-voltage p-channel-type transistor in the semiconductor substrate,
 wherein a step in which the high-breakdown-voltage p-channel-type transistor is formed comprises:   preparing the semiconductor device, which comprises the semiconductor substrate having the main surface and further having, in the internal region thereof, the p-type region;   forming a first n-type semiconductor layer inside the semiconductor substrate and at the main-surface-side of the p-type region;   forming a first p-type dopant for taking out a drain electrode over the p-type region and in/on the main surface;   forming a second p-type region for taking out a source electrode over the p-type region and in/on the main surface; and   forming a local n-type buried region just below the first p-type dopant region to contact the first n-type semiconductor layer,   wherein the same mask is used to conduct the step of forming the first p-type dopant region and the step of forming the local n-type buried region.   
     
     
         2 . The method for producing a semiconductor device according to  claim 1 , wherein the semiconductor substrate further comprises a high-breakdown-voltage n-channel-type transistor comprising a second n-type semiconductor layer as a layer identical to the first n-type semiconductor layer of the high-breakdown-voltage p-channel-type transistor, and a step of forming the second n-type semiconductor layer of the high-breakdown-voltage n-channel-type transistor is performed simultaneously with the step of forming the first n-type semiconductor layer of the high-breakdown-voltage p-channel-type transistor. 
     
     
         3 . The method for producing a semiconductor device according to  claim 2 , wherein the local n-type buried region is formed by an ion implantation method. 
     
     
         4 . The method for producing a semiconductor device according to  claim 2 , wherein the first p-type dopant region is formed by an ion implantation method. 
     
     
         5 . The method for producing a semiconductor device according to  claim 2 , wherein the first n-type semiconductor layer is formed by an ion implantation method.