Browse Prior Art Database

Bipolar Field-Effect Transistor

IP.com Disclosure Number: IPCOM000046407D
Original Publication Date: 1983-Jul-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Huang, YS: AUTHOR [+2]

Abstract

A multi-purpose device, having the combined characteristics of a unipolar and bipolar transistor, serves as a field effect-enhanced lateral bipolar transistor or a bipolar-enhanced variable resistor or other combined bipolar/field-effect-type device.

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Bipolar Field-Effect Transistor

A multi-purpose device, having the combined characteristics of a unipolar and bipolar transistor, serves as a field effect-enhanced lateral bipolar transistor or a bipolar-enhanced variable resistor or other combined bipolar/field-effect-type device.

Referring to the figures, Fig 1A is the vertical cross-section and Fig. 1B is the top-view of the device. A P-type semiconductor substrate 8 is provided with a heavily doped N-type layer 7. A lightly doped N-type epitaxial layer 5 is grown over the substrate 8.

Heavily doped p-type regions l and 3 are formed in the epitaxial layer 5. Moderately doped p-type region 2, moderately or heavily doped N-type region 4, and heavily doped N-type region 6 are also formed. Isolation 9 and 10 are used to isolate the device or junctions.

To operate the device as a field-effect enhanced lateral PNP transistor, "l" is used as an emitter and "3" as a collector. "4" serves as a depletion gate to deplete the majority carriers in the channel 2, and "5" serves as an enhancement gate to modulate the majority carriers in the channel 2 and as the bipolar base to turn-on or turn-off the P-N junction between "l" and "5". The P-N junctions between "3" and "4", and "3" and "5" are reverse-biased. Region 5 is externally contacted through "6" and "7". The unipolar carrier transfer through the channel 2 and the lateral PNP bipolar carrier transfer can be properly controlled by the gates 4 and 5. Gates 4 and 5 can al...