Abstract: 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.

Abstract: 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 “zeroed” on the retroreflected signal such that the subsequent measurements recorded by the first photodetector are a precise measurement of the grating period.

Abstract: 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.

Abstract: 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.