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Use Of Pre Source Chamber In Open Tube Vapor Growth Systems

IP.com Disclosure Number: IPCOM000096777D
Original Publication Date: 1963-Nov-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Lever, RF: AUTHOR [+2]

Abstract

In the germanium bromine open tube process for epitaxial germanium crystal growth, growth of the germanium seed is readily attained. Such is when the source bed temperature exceeds the seed crystal temperature by at least 50 degrees C. At temperature differences delta T less than 50 degrees C., growth does not readily occur. For degrees T less than 30 degrees C., etching of the seed sometimes occurs. It is thus necessary that the flowing gas stream come to equilibrium with the source, a bed of crushed germanium lumps approximately eight inches long.

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Use Of Pre Source Chamber In Open Tube Vapor Growth Systems

In the germanium bromine open tube process for epitaxial germanium crystal growth, growth of the germanium seed is readily attained. Such is when the source bed temperature exceeds the seed crystal temperature by at least 50 degrees C. At temperature differences delta T less than 50 degrees C., growth does not readily occur. For degrees T less than 30 degrees C., etching of the seed sometimes occurs. It is thus necessary that the flowing gas stream come to equilibrium with the source, a bed of crushed germanium lumps approximately eight inches long.

Attainment of equilibrium in the source bed of a germanium bromine open tube epitaxial germanium vapor growth system can be facilitated. This is by passing the gas through a pre-source bed before passing it through the actual source bed. This pre-source bed is similar to the actual source but is at an appreciably higher temperature, e. g., 30 degrees C. higher than the source. By adjustment of pre-source temperature and flow conditions, the composition of the gas entering the source chamber can be arranged to be very close to that value which would be in equilibrium with the source. This reduces the reaction necessary at the source to achieve equilibrium.

In this way, only a very small amount of etching of the source, or deposit on the source, is required to attain equilibrium. In the latter case, there is a possible added advantage that the source will be co...