Surface Technology Systems Plc

Comlase Ab

Carl-Fredrik Carlstrom

Anand Srinivasan

N Peter Blixt

Christofer Silvenius

Svante Soderholm

Lauerant Krummenacher

Gunnar Landgren

L Karsten V Lindstrom

A substrate whose elemental constituents are selected from Groups III and V of the Periodic Table, is provided with pre-defined masked regions. Etching of the substrate comprising the steps of: a) forming a gas containing molecules having at least one methyl group (CH) linked to nitrogen into a plasma; and b) etching the unmasked regions of the substrate by means of the plasma. For a substrate whose elemental constituents are selected from Groups II and VI of the Periodic Table, the plasma etching gas used is trimethylamine. Since the methyl compound of nitrogen has a lower bond energy than for hydrocarbon mixtures, free methyl radicals are easier to obtain and the gas is more efficient as a methyl source. In addition, compared with hydrocarbon mixtures, reduced polymer formation can be expected due to preferential formation of methyl radicals over polymer-generating hydrocarbon radicals because of the lower bond energy for the former.

Plasma etching

The invention relates to a method using dry etching to obtain contamination free surfaces on of a material chosen from the group comprising GaAs, GaAlAs, InGaAsP, and InGaAs to obtain nitride layers on arbitrary structures on GaAs based lasers, and a GaAs based laser manufactured in accordance with the method. The laser surface is provided with a mask masking away parts of its surface to be prevented from dry etching. The laser is then placed in vacuum. Dry etching is then performed using a substance chosen from the group containing: chemically reactive gases, inert gases, a mixture between chemically reactive gases and inert gases. A native nitride layer is created using plasma containing nitrogen. A protective layer and/or a mirror coating is added.

Method to GaAs based lasers and a GaAs based laser

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Farsta, Sweden

Carl-Fredrik Carlstrom