Semiconductor device and method for fabricating the same

摘要

A semiconductor device includes a laterally double diffused metal oxide semiconductor (LDMOS) transistor formed on a partial region of a epitaxial layer of a first conductive type, a bipolar transistor formed on another partial region of the epitaxial layer of the first conductive type, and a guard ring formed between the partial region and the another partial region. The guard ring serves to restrain electrons generated by a forward bias operation of the LDMOS transistor from being introduced into the bipolar transistor.

主权项

1. A semiconductor device, comprising:
a laterally double diffused metal oxide semiconductor (LDMOS) transistor formed on a first portion of an epitaxial layer, wherein the epitaxial layer is a first conductive type; a bipolar transistor formed on a second portion of the epitaxial layer; and a guard ring formed between the first portion of the epitaxial layer and the second portion of the epitaxial layer, wherein the guard ring substantially prevents electrons generated by a forward bias operation of the LDMOS transistor from moving into the bipolar transistor when an isolation voltage is applied to the guard ring, wherein the bipolar transistor comprises:
a buried layer of a second conductive type, wherein the buried layer is connected to the guard ring,a second extension region of the first conductive type having a contact surface with the buried layer, the second extension region is formed through a ion implantation of a first conductive type impurity,a first extension region of the second conductive type formed within the second extension region, wherein the first extension region includes a collector region and an emitter region, anda base region formed between the guard ring and the second extension region.