Etch method of cleaving semiconductor diode laser wafers

Abstract

Double heterostructure (Al,Ga)As wafer comprising layers of gallium arsenide and aluminum gallium arsenide on a metallized n-GaAs substrate are separated into individual devices for use as diode lasers. In contrast to prior art techniques of mechanically cleaving the wafer in mutually orthogonal directions, the wafer is first separated into bars of diodes by a process which comprises (a) forming an array of exposed lines on the n-side by photolithography to define the lasing ends of the diodes, (b) etching through the exposed metallized portion to expose portions of the underlying n-GaAs, (c) etching into the n-GaAs substrate with a V-groove etchant to a distance of about 1 to 2 mils less than the total thickness of the wafer and (d) mechanically cleaving into bars of diodes. The cleaving may be done by prior art techniques using a knife, razor blade or tweezer edge or by attaching the side of the wafer opposite to the V-grooves to a flexible adhesive tape and rolling the assembly, such as over a tool of small radius. The diode bars may then, following passivation, be further cleaved into individual diodes by the prior art techniques of mechanically scribing and cleaving. Processing in accordance with the invention improves length definition and uniformity, increases device yields and reduces striations on lasing facets, as compared with prior art techniques.

Dependencies are inferred from the claim text.