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Vapor Etching of Gallium Arsenide

IP.com Disclosure Number: IPCOM000091432D
Original Publication Date: 1968-Jan-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Blakeslee, AE: AUTHOR [+2]

Abstract

In the case of epitaxial growth of gallium arsenide crystals, it is necessary to vapor etch the substrate in situ in the epitaxial reactor just prior to beginning the growth of the epitaxial layer. This vapor etching produces a new clean surface for the layer to grow upon, thus optimizing either the structural or electrical properties or both of the epitaxial deposit.

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Vapor Etching of Gallium Arsenide

In the case of epitaxial growth of gallium arsenide crystals, it is necessary to vapor etch the substrate in situ in the epitaxial reactor just prior to beginning the growth of the epitaxial layer. This vapor etching produces a new clean surface for the layer to grow upon, thus optimizing either the structural or electrical properties or both of the epitaxial deposit.

One system for epitaxial growth of gallium arsenide is using arsenic trichloride vapor passing over gallium and then over the gallium arsenide substrate. In this system, the vapor etching is done by adjusting the temperature to values other than those used for epitaxial growth. This is a time-consuming process. It leads to instability and nonreproducibility because of the changing temperatures, and sharp impurity gradients at the epitaxial interface are difficult to produce. In contrast to the above-mentioned method, vapor etching can be performed faster, more easily, and more reproducibly by leaving the temperature profile unchanged but altering the composition of the gas phase, i.e., by increasing or decreasing the percentage of hydrogen in the reaction gas. This is accomplished by opening and closing a valve to regulate the flow of hydrogen.

In this system, epitaxial growth is performed with a flow rate of 200cc/min of hydrogen bubbling through arsenic trichloride and thence into the reactor. If it is started off with another 200cc/min or pure hydrogen mixed into...