US 7,741,186 B2 · Creating increased mobility in a bipolar device

Abstract

The mobility of charge carriers in a bipolar (BJT) device is increased by creating compressive strain in the device to increase mobility of electrons in the device, and creating tensile strain in the device to increase mobility of holes in the device. The compressive and tensile strain are created by applying a stress film adjacent an emitter structure of the device and atop a base film of the device. In this manner, the compressive and tensile strain are located in close proximity to an intrinsic portion of the device. A suitable material for the stress film is nitride. The emitter structure may be “T-shaped”, having a lateral portion atop an upright portion, a bottom of the upright portion forms a contact to the base film, and the lateral portion overhangs the base film.

Claims7

Dependent claims

A method of increasing mobility of charge carriers in a bipolar device comprising the steps of:

applying a conformal stress film atop and in direct contact with exposed surfaces of a base film, the base film being disposed atop a collector region of the bipolar device;
applying the conformal stress film adjacent an emitter structure of the bipolar device and atop the base film;
applying the conformal stress film to cover and be in direct contact with exposed surfaces of the emitter structure;
creating compressive strain in the device with the conformal stress film to increase mobility of holes in the device;
and
creating tensile strain in the device with the conformal stress film to increase mobility of electrons in the device.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application

11/946,940Filed 29 Nov 2007 · division

Priority

20 Jul 2004

Published

US 2008/0067631 A120 Mar 2008

Granted

22 Jun 2010

Term ends

Not estimatedThe source records don’t support an estimate.

Classification10 codes

H10D 10/021
Manufacture or treatment: of heterojunction BJTs [HBT]
H10D 10/051
Manufacture or treatment: of vertical BJTs
H10D 10/40
Bipolar junction transistors [BJT]: vertical BJTs
H10D 10/891
Vertical heterojunction BJTs: comprising lattice-mismatched active layers, e.g. SiGe strained-layer transistors

Creating increased mobility in a bipolar device

Life of this patent

Creating increased mobility in a bipolar device

Life of this patent

Abstract

Claims7