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Producing Semiconductor Devices by Oriented Lateral Overgrowth

IP.com Disclosure Number: IPCOM000091516D
Original Publication Date: 1968-Mar-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Von Muench, W: AUTHOR

Abstract

This technique is for making a semiconductor device of the FET type. One problem in developing field-effect transistors FET' s, especially Schottky barrier devices for high-speed operation, is to reduce the resistance between the source and gate regions. To a certain extent, this can be accomplished by reducing the physical dimensions of the semiconductor device. There are physical limitations, e.g., in the masking techniques, which do prevent further reduction.

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Producing Semiconductor Devices by Oriented Lateral Overgrowth

This technique is for making a semiconductor device of the FET type. One problem in developing field-effect transistors FET' s, especially Schottky barrier devices for high-speed operation, is to reduce the resistance between the source and gate regions. To a certain extent, this can be accomplished by reducing the physical dimensions of the semiconductor device. There are physical limitations, e.g., in the masking techniques, which do prevent further reduction.

In this device, use is made of the fact that, for certain semiconductor materials, epitaxial growth proceeds with different velocities in different crystallographic orientations, e.g., <111>. For the III-V compounds there is also a difference between the growth rates on the (111)-faces terminated with group III atoms, and on the (111)-faces, terminated with group V atoms. The usual ratios of growth rates are about 5:1.

In this fabrication process, a semiconductor substrate is partly masked by masking layer 2 as in A. Epitaxial growth 3 starts in the holes as defined by the mask geometry in B. As long as the growing area is laterally limited by the mask surrounding the holes, the process proceeds conventionally. However, when the epitaxially grown semiconductor material exceeds the level of the mask and, if the direction of rapid growth is chosen to be parallel to the surface of the mask, the epitaxial growth process proceeds with a higher spee...