US Patent 7892860 Semiconductor laser chip and method of formation thereof

A method for forming a semiconductor laser chip is provided that can suppress layer discontinuity and simultaneously reduce fabrication variations in the light radiation angle in the horizontal direction. The method includes a step of forming, on an n-type GaAs substrate, a semiconductor element layer composed of a plurality of semiconductor layers including an etching marker layer, a step of forming, in a contact layer in the semiconductor element layer, a depressed portion having a depth not reaching the etching marker layer, and a step of forming a ridge portion by etching the semiconductor element layer by dry etching while monitoring, with laser light, the etching depth in the bottom region of the depressed portion.