US 2017/0373174 A1Published application

Radiation enhanced bipolar transistor

AssigneeTexas Instruments Incorporated

InventorsJames Fred Salzman, Randolph William Kahn, Richard Guerra Roybal

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Abstract

Disclosed examples include integrated circuits and bipolar transistors with a first region of a first conductivity type in a substrate, a collector region of a second conductivity type disposed in the substrate, and a base region of the first conductivity type extending into the first region. A first emitter region of the second conductivity type extends into the first region and includes a lateral side spaced from and facing the base region. A second emitter region of the second conductivity type extends downward into the first region, abutting the top surface and an upper portion of the first lateral side of the first emitter region to mitigate surface effects and gain degradation caused by hydrogen injection from radiation to provide a radiation hardened bipolar transistor.

Claims20

Dependent claims

A bipolar transistor, comprising:

a semiconductor substrate, including a top surface;
a first region of a first conductivity type extending downward into the substrate from the top surface, the first region having a first doping concentration;
a collector region of a second conductivity type disposed in the substrate;
a base region of the first conductivity type extending downward into the first region from the top surface and abutting the top surface, the base region having a second doping concentration greater than the first doping concentration;
a first emitter region of the second conductivity type extending downward into the first region and abutting the top surface, the first emitter region having a third doping concentration, the first emitter region including a first lateral side spaced from and facing the base region;
and
a second emitter region of the second conductivity type extending downward into the first region, the second emitter region abutting the top surface and abutting an upper portion of the first lateral side of the first emitter region, the second emitter region having a fourth doping concentration less than the third doping concentration.

4 more elements

An integrated circuit (IC), comprising:

a semiconductor substrate, including a top surface;
a first region of a first conductivity type extending downward into the substrate from the top surface, the first region having a first doping concentration;
a collector region of a second conductivity type disposed in the substrate;
a base region of the first conductivity type extending downward into the first region from the top surface and abutting the top surface, the base region having a second doping concentration greater than the first doping concentration;
a conductive base contact abutting the base region above the top surface;
a first emitter region of the second conductivity type extending downward into the first region and abutting the top surface, the first emitter region having a third doping concentration, the first emitter region including a first lateral side spaced from and facing the base region;
a conductive emitter contact abutting the first emitter region above the top surface;
and
a second emitter region of the second conductivity type extending downward into the first region, the second emitter region abutting the top surface and abutting an upper portion of the first lateral side of the first emitter region, the second emitter region having a fourth doping concentration less than the third doping concentration.

6 more elements

A method to fabricate a bipolar transistor, the method comprising:

implanting dopants of a first conductivity type into a semiconductor substrate to form a first region extending downward from a top surface of the substrate, the first region having a first doping concentration;
implanting dopants of the first conductivity type to form a base region extending downward into the first region from the top surface and abutting the top surface, the base region having a second doping concentration greater than the first doping concentration;
implanting dopants of a second conductivity type to form a first emitter region extending downward into the first region and abutting the top surface, the first emitter region having a third doping concentration, the first emitter region including a first lateral side spaced from and facing the base region;
implanting dopants of the second conductivity type to form a second emitter region extending downward into the first region, the second emitter region abutting the top surface and abutting an upper portion of the first lateral side of the first emitter region, the second emitter region having a fourth doping concentration less than the third doping concentration;
forming a conductive base contact abutting the base region above the top surface;
forming a conductive emitter contact abutting the first emitter region above the top surface;
and
forming a metallization structure over the top surface of the substrate, the metallization structure including conductive structures to allow external connection to the base contact and the emitter contact.

5 more elements

Dependencies are inferred from the claim text.