General Instrument Corporation

Other

Ali Salih

Dennis Garbis

Joseph Y Chan

Gregory Zakaluk

Lawrence LaTerza

Reinhold Hirtz

An all epitaxial process performed entirely in a CVD reactor is employed to grow heavily doped layer on lightly doped layer on a heavily doped substrate, eliminating the need for separate diffusion, even for high impurity concentrations. The process starts with a heavily doped silicon substrate of carrier concentration typically greater than 1.times.10.sup.19 per cm.sup.3. To minimize outdiffusion, the substrate is 'capped' by growing very thin and heavily doped silicon layers which are depleted by hydrogen purges. A first epitaxial layer is grown over the 'capped' substrate. This layer is relatively lightly doped, having a resistivity of more than 200 ohm.cm. A second epitaxial layer is then grown over the first epitaxial layer. The second epitaxial layer has a polarity opposite to that of the substrate and is heavily doped to a resistivity of less than 0.005 ohm cm.

Method for fabricating a multilayer epitaxial structure

The switching speed of bipolar power rectifiers is increased by formation of misfit dislocations in the depletion region, spaced from the substrate/epitaxial layer interface, in order to reduce minority carrier lifetime. The misfit dislocations are formed by the introduction of germanium during epitaxy, and are distributed along the silicon/silicon-germanium interface. Preferably, the germanium containing layer is located proximate the center of the depletion region.

Method for controlling the switching speed of bipolar power devices

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Ali Salih