British Telecommunications Public Limited Company

British Telecommunications Corporation

Simon Cole

Ian F Lealman

Andrew W Nelson

William J Devlin

David M Cooper

Paul C Spurdens

Michael J Harlow

Stanley Y Wong

Joseph J Isaac

David Martin Cooper

William John Devlin

Ian Francis Lealman

Stanley Yk Wong

Semiconductor laser amplifiers

In a semiconductor buried heterostructure laser having a mesa (2, 3, 4) and confinement layers (5, 6, 7) on a substrate (12), at least the lowermost of the confinement layers (5, 6, 7) is substantially planar up to the mesa. This is achieved by MOVPE growth of InP against lateral surfaces of the mesa (2, 3, 4) which are defined by distinct crystallographic planes of the material of the mesa. In particular (111) B InP planes are used. The laser is particularly for use in the field of optical communications.

Method of manufacturing semiconductor structures

It has been found that layers which include arsenic and/or zinc can have an adverse effect upon optoelectronic semiconductor devices such as lasers. This is reduced by treatments in which arsenic and zinc are excluded. Preferably the substrate is cooled from reaction temperature in the presence of a mixture of hydrogen and PH.sub.3 (replacing AsH.sub.3 and/or Zn(CH.sub.3).sub.2 used to grow the final layer). Alternatively, devices have a contact layer of heavily p-type gallium indium arsenide are improved by the deposition of a protective layer of indium phosphide. This layer is removed immediately before metalization. Even though the protective layer is not present in the final product it has a beneficial effect.

Preparation of semiconductor devices

Growing community of inventors

Ipswich, United Kingdom

Simon Cole