| 摘要 |
PURPOSE:To prevent development of constriction at a mesa side by forming a mesa structure by making selective etching to an epitaxial wafer surface whereon a multilayer structure of double hetero structure consisting of InP and InGaAsP is formed and by treating a wafer surface with alcoholoc solution containing a specified amount of bromine after a mask is removed. CONSTITUTION:An N-type InP buffer layer 2, an IaGaAsP active layer 3, a P-type InP clad layer 4, and a P-type InGaAsP cap layer 5 are successively formed on an N-type InP substrate 1 through epitaxial growth method. Thereafter, a mask 6 is formed for mesa etching through photolithography. After etching is made by using etchant consisting of bromine, methanol and phosphoric acid to form a mesa structure, a mask 6 is removed and a wafer is left in methanol solution or ethanol solution which is static at a room temperature and contains bromine of about 0.1% at capacity rate for 20sec or 40sec. After a crystal surface is etched slightly and cleaned, an insulating film for current constriction is attached. |
