High-voltage field effect transistor having isolation structure

摘要

A high-voltage MOSFET having isolation structure is provided. An N-type MOSFET includes a first deep N-type well. A first P-type region is formed in the first deep N-type well to enclose a first source region and a first contact region. A first drain region is formed in the first deep N-type well. A P-type MOSFET includes a second deep N-type well. A second P-type region is formed in the second deep N-type well to enclose a second drain region. A second source region and a second contact region are formed in the second deep N-type well. A polysilicon gate oxidation layer is disposed above the thin gate oxidation layer and the thick field oxidation layer to control the current in the channel of the MOSFET. Separated P-type regions provide further isolation between MOSFETs. A first gap and a second gap increase the breakdown voltage of the high-voltage MOSFET.