Combined DMOS and a vertical bipolar transistor device and fabrication method therefor

US4344081A · kind A · utility

Assignee

• Supertex, Inc. · US

Inventors

• Henry Pao · Cary, US
• Richard A. Blanchard · Los Altos, US
• Benedict C. K. Choy · Campbell, US

Key dates

• Filing date: Apr 14, 1980
• Grant date: Aug 10, 1982
• Expiry date: Apr 14, 2000

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D84/406

Abstract

This disclosure relates to an improved DMOS semiconductor type device which can function both as a DMOS (unipolar) type device and as a bipolar transistor device. The DMOS device has two separated source regions of, for example, N+ conductivity and each of these source regions is surrounded by a P- type region, thus providing a pair of channels between each N+ source region and a common N type drain region located between the P- regions. A gate electrode is disposed over both of the channels and functions to permit electrons from the N+ source regions to flow across the P- channels into the common N type drain region when a proper bias is applied to the gate region. Each of the source regions has its own electrode and a separate electrode is provided to each of the P- regions that surround each of the respective N+ source regions. Thus, the DMOS type structure can function as a DMOS device with the electrodes to the source regions serving as source electrodes and the gate electrode functioning to permit electron flow from the separated source regions to a common drain region. Alternatively, one of the electrodes to the N+ source region could function as an emitter (or a source elec…