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Fabricating Injection Lasers

IP.com Disclosure Number: IPCOM000094334D
Original Publication Date: 1966-Sep-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Bayer, EH: AUTHOR [+2]

Abstract

A GaAs substrate which is masked with SiO(2), is used in a solution regrowth apparatus to fabricate injection lasers. The solution regrowth apparatus is a vertical structure in which a P-type, Zn doped GaAs substrate is mounted on a rod which can be moved vertically within the apparatus. The melt, which includes Ga, GaAs, and Te, an N-type impurity in GaAs, is first heated up to a temperature at which it is entirely liquid.

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Fabricating Injection Lasers

A GaAs substrate which is masked with SiO(2), is used in a solution regrowth apparatus to fabricate injection lasers. The solution regrowth apparatus is a vertical structure in which a P-type, Zn doped GaAs substrate is mounted on a rod which can be moved vertically within the apparatus. The melt, which includes Ga, GaAs, and Te, an N-type impurity in GaAs, is first heated up to a temperature at which it is entirely liquid.

The equilibrium temperature for the melt is determined by lowering the temperature until solid GaAs appears on the melt surface. The temperature is then raised about 50 degrees C until all solid residues are dissolved and then slowly cooled. At a temperature about 10 degrees C above the equilibrium temperature the masked substrate of GaAs is lowered close to the melt surface and allowed to reach thermal equilibrium. The cooling rate is meanwhile reduced to 0.8 degrees C per min.

At 8 degrees C above the equilibrium temperature the wafer is dipped into the melt and retracted again after one minute at which time the temperature is about 7 degrees C above the equilibrium point. As a result, regrown regions are formed on the unmasked portions of the substrate. When the unmasked portions of the wafer are narrow, nonuniform wetting can be avoided by treating the wafer surface prior to regrowth with a thin film of a mixture of gallium and indium, close to the eutectic composition, at 300 degrees K.

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