SEMICONDUCTOR DEVICE WITH HIGH BREAKDOWN VOLTAGE AND MANUFACTURE THEREOF

摘要

A semiconductor device includes: first and second n-type wells formed in p-type semiconductor substrate, the second n-type well being deeper than the first n-type well; first and second p-type backgate regions formed in the first and second n-type wells; first and second n-type source regions formed in the first and second p-type backgate regions; first and second n-type drain regions formed in the first and second n-type wells, at positions opposed to the first and second n-type source regions, sandwiching the first and the second p-type backgate regions; and field insulation films formed on the substrate, at positions between the first and second p-type backgate regions and the first and second n-type drain regions; whereby first transistor is formed in the first n-type well, and second transistor is formed in the second n-type well with a higher reverse voltage durability than the first transistor.

主权项

1. A method of manufacturing a semiconductor device comprising:
forming a first n-type well by ion implantation of an n-type impurity into a p-type semiconductor substrate; diffusing the n-type impurity of the first n-type well by heat treatment, thereby forming a first enlarged n-type well with an increased depth; forming isolation films in the p-type semiconductor substrate; forming a second n-type well by ion-implantation of an n-type impurity in the p-type semiconductor substrate, the second n-type well being shallower than the first enlarged n-type well; forming a first and a second p-type backgate regions by ion-implantation of a p-type impurity in the first enlarged n-type well and the second n-type well; forming a first and a second gate electrode extending from above the first and the second backgate region onto the isolation films; forming a first and a second n-type source region by ion-implantation of an n-type impurity in the first and the second backgate regions; and forming a first and a second n-type drain region by ion-implantation of an n-type impurity at positions opposing to the first and the second n-type source regions with the first and second backgate regions and the field insulation films in the first enlarged n-type well and the second n-type well located in between.