Patent ID: 6613679
Filing Date: 2003-09-02
Classification: H01L,H01S

Abstract:
A method for fabricating a semiconductor device with a compound semiconductor layer, the method comprising the steps of:a) depositing a masking film on a first compound semiconductor layer formed on a semiconductor substrate; b) patterning the masking film so that the film has an opening; c) etching away at least an uppermost part of the first compound semiconductor layer which part is located inside the opening and includes a degraded layer formed in the step a) or b), using a first etchant and the masking film; and d) patterning the first compound semiconductor layer by etching away another part of the first compound semiconductor layer using a second etchant and masking film, wherein said another part is located inside the opening and does not include the uppermost part with the degraded layer, wherein the second etchant allows for etching the first compound semiconductor layer at a rate lower than a rate realized by the first etchant, wherein the degraded layer includes at least one of: a damaged layer that has a composition deviated from a stoichiometric composition of elements in the first compound semiconductor layer; an oxide layer of the first compound semiconductor layer; and a reactant layer formed through a reaction of the first compound semiconductor layer with a reactive gas for use in the dry etching process, wherein in the step a), an uppermost part of the substrate is a second compound semiconductor layer, and wherein the method further comprises the step of patterning the second semiconductor layer using a remaining part of the first semiconductor layer as a mask after the first layer has been patterned in the step d).