At&t Bell Laboratories

Lucent Technologies Inc.

Agere Systems Guardian Corp.

Jerome Levkoff

Daniel C Sutryn

John W Benko

Montri Viriyayuthakorn

John William Stayt, Jr

Frank Stephen Walters

Edward J Flynn

Julie Eng

Erick John Michel

Anthony D Mazzatesta

The invention is a method of fabricating a semiconductor device involving selectively etching at least a first semiconductor layer on a semiconductor wafer so as to perform a lateral taper etch in said layer, forming a second layer over the resulting etched region so as to planarize the etched area, and subsequently performing a second etch over a portion of the etched region so as to form a mesa geometry. This material allows device fabrication with a lateral taper, beneficial to monolithic integration of devices, such as expanded beam lasers, while reducing or eliminating unwanted increases in mesa width (mesa bulge) resulting from the lateral taper.

Method of fabricating a semiconductor mesa device

A precision grating period measurement system uses a pair of properly positioned photodetectors to provide sub-Angstrom resolution. That is, the absolute position of a first detector with respect to a zero point in the measurement system is assured by including a second photodetector that measures a retroreflected signal. The system is then &ldquo;zeroed&rdquo; on the retroreflected signal such that the subsequent measurements recorded by the first photodetector are a precise measurement of the grating period.

Precision grating period measurement arrangement

In an MOCVD reactor, gases are channeled around the periphery of a baffle plate (15) so as to flow radially inwardly along a slotted injection plate (16). The slots (22) in the injection plate extend radially and are of non-uniform width so as to compensate for a non-uniform rate of deposition. The resultant flow over a rotating heated substrate (17) gives a more uniform deposit of epitaxially grown material.

MOCVD method and apparatus

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Sinking Spring, PA, United States of America

Jerome Levkoff