FABRICATION OF SEMICONDUCTOR LASER

PURPOSE:To realize a semiconductor laser in which the thickness of protective film can be formed with high controllability by forming the protective film for the emission edge by Langmuir-Blodgett method. CONSTITUTION:An n-type current block layer 2, a lower clad layer 3 of P-type AlGaAs, a P-type active layer 4, an upper clad layer 5 of n-type AlGaAs, an n-type contact layer 6, and an electrode 7 are deposited sequentially on a P-type GaAs wafer 1 to obtain a desired semiconductor laminate structure. Subsequently, the wafer is cleaved to obtain a semiconductor chip bar 15. In order to form a dielectric protective film only on the emission edge 8, the electrode 7 forming face and the like are previously covered and the semiconductor chip bar 15 is shifted up and down with respect to the interface of an aqueous liquid medium, on which a single molecular film of an amphiliphic organic substance 12 is formed, while keeping the axis thereof normal to the interface. This method allows thickness control of the dielectric protective film in the molecular order thus realizing a high quality, low noise semiconductor laser.