Abstract: A GaN compound semiconductor laser includes an AlGaN buried layer which buries opposite sides of a ridge stripe portion formed on a p-type AlGaN cladding layer. The AlGaN buried layer is made by first patterning an upper part of the p-type AlGaN cladding layer and a p-type GaN contact layer into a ridge stripe configuration by using a SiO2 film as an etching mask, then growing the AlGaN buried layer non-selectively on the entire substrate surface to bury both sides of the ridge stripe portion under the existence of the SiO2 film on the ridge stripe portion, and thereafter selectively removing the AlGaN buried layer from above the ridge stripe portion by etching using the SiO2 film as an etching stop layer. Thus, the GaN compound semiconductor laser is stabilized in the transverse mode, intensified in output power, and improved in lifetime.

Abstract: A method for fabricating a semiconductor device improves step coverage and resistivity. The method includes the steps of forming a doped silicon layer on a substrate, forming a silicide layer containing more metal atoms than silicon atoms on the doped silicon layer, and heat treating in nitrogen to form a second silicide layer having a tetragonal phase crystal structure and a silicon nitride film on the top surface of the second silicide layer.