FAST SWITCHING PNP TRANSISTOR

• US 3,571,674 A
• Filed: 01/10/1969
• Issued: 03/23/1971
• Est. Priority Date: 01/10/1969
• Status: Expired due to Term

• Current Assignee: Edward H. Snow, Yu Albert Y C
• Original Assignee: Edward H. Snow, Yu Albert Y C
• Inventors: YU ALBERT Y C, Snow, Edward H.
• Application Number:
  US04/790,317
• Time in Patent Office: 802 Days
• US Class Current: 257/474
• CPC Class Codes: H01L 27/00 Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate details thereof H01L23/00, H01L29/00 - H10K10/00; assemblies consisting of a plurality of individual solid state devices H01L25/00
• CPC Class Codes: H01L 27/0766 with Schottky diodes only
• CPC Class Codes: H01L 27/0783 Lateral bipolar transistors in combination with diodes, or capacitors, or resistors
• CPC Class Codes: Y10S 148/037 Diffusion-deposition
• CPC Class Codes: Y10S 148/085 Isolated-integrated
• CPC Class Codes: Y10S 148/096 Lateral transistor

Abstract

The on-off switching time of a PNP transistor is significantly decreased by placing a Schottky Barrier diode in parallel with the collector-base PN junction of the transistor.

Claims

2. Structure as in claim 1 wherein said Ohmic contacts comprise a metal selected from the group consisting of aluminum, gold, nickel, platinum and molybdenum and said metal layer likewise comprises a metal selected from this same group of metals.

3. Structure as in claim 2 wherein said collector, base and emitter regions comprise selectively doped silicon, said ohmic contacts comprise aluminum, and said metal layer comprises aluminum.

4. A fast switching transistor comprising:

a P-type collector region with an impurity concentration ranging from 1014 to 1017 atoms per cubic centimeter;

an N-type base region epitaxially-grown on said P-type collector region with an impurity concentration no greater than about 1017 atoms per cubic cubic centimeter;

a P-type emitter region diffused into, and forming a PN junction with said epitaxially-grown N-type region, said emitter region having an impurity concentration of approximately 1019 atoms per cubic centimeter;

selected ohmic contacts to said emitter, said base and said collector regions;

a Schottky Barrier diode connecting said base region to said collector region, said Schottky Barrier diode comprising a metal layer attached to adjacent portions of both said P-type collector region and said epitaxilally-grown N-type base region, thereby to form a Schottky Barrier junction with said N-type base region and an ohmic junction with said P-type collector region; and

an extension of said metal layer on insulation over a portion of said epitaxially grown N-type base region, thereby to shape the electric field in said N-type base region to improve the breakdown voltage of said Schottky Barrier junction.

5. A fast-switching transistor comprising:

a P+-type collector region;

an N-type base region epitaxially-grown on said P+-type collector region;

a P+-type emitter region diffused into, and forming a PN junction with said epitaxially-grown N-type region;

a P+-type collector contact region diffused through said epitaxially-grown N-type region into contact with said P+-type collector region;

selected ohmic contacts to said emitter, said base and said collector contact regions;

a Schottky Barrier diode connecting said base region to said collector region, said Schottky Barrier diode comprising a metal layer attached to adjacent portions of both said P+-type collector contact region and said epitaxially-grown N-type base region, thereby to form a Schottky Barrier junction with said N-type base region and an ohmic junction with said P+-type collector contact region; and

an extension of said metal layer on insulation over a portion of said N-type base region, thereby to shape the electric field in said N-type base region to improve the breakdown voltage of said Schottky Barrier junction.