American Telephone & Telegraph Co., At&t Bell Laboratories

At&t Bell Laboratories

Chung Y Chen

Alfred Yi Cho

Sung-Nee George Chu

Clyde G Bethea

We have found that transistors have desirable device characteristics when the base region is composed of a lightly doped layer near the emitter junction and a heavily doped layer near the collector junction. The edge of the depletion region at the emitter-base junction is designed to stop in the lightly doped base region.

Depletion stop transistor

Useful field effect transistors can be made with gallium indium arsenide as the electron conducting layer (channel layer) by incorporating a layer of gallium arsenide for the Schottky barrier. Relatively thick gallium arsenide layers are used to achieve low reverse leakage currents.

Gallium arsenide on gallium indium arsenide Schottky barrier device

A modulation-doped field effect photodetector has a fast response time.

Modulation-doped photodetector

A new technique called stop cleaving permits semiconductor lasers having etched mirrors to be fabricated on a common substrate with other optical or electronic components such as photodetectors and field-effect transistors.

Integrated devices including cleaved semiconductor lasers

A high speed bias-free photodetector which capacitively couples the output signal to an external circuit is described.

High speed bias-free photodetector

A thin and highly doped Ga.sub.0.47 In.sub.0.53 As layer disposed on a Ga.sub.0.47 In.sub.0.53 As layer increases the barrier height and produces useful device characteristics. For example, the structure may be used as the gate electrode in an InGaAs field effect transistor.

MESFET Using a shallow junction gate structure on GaInAs

A majority carrier photodetector has high sensitivity and fast response times. The photodetector comprises a thin highly doped layer surrounded on either side by two nominally undoped layers which are completely depleted at thermal equilibrium.

Growing community of inventors

Scotch Plains, NJ, United States of America

Chung Y Chen