DIFFUSION OF GROUP II IMPURITY TO INP OR INGAASP SUBSTRATE

摘要

PURPOSE:To enable excellent impurity diffusion, through which the defect of a pinhole, etc., are hardly generated, by a method wherein an In0.53Ga0.47As epitaxial growth layer is formed on an InP substrate, to which a group II impurity is diffused, an Si3N4 film as a diffusion preventive film is formed through a thermal CVD method, the impurity is diffused selectively through a vacuum sealing method, and the Si3N4 selective diffusion film and the In0.53Ga0.47As layer are removed. CONSTITUTION:An N-type or intrinsic In0.53Ga0.47As layer 4 is formed onto an InP or InGaAsP wafer 1, an Si3N4 diffusion preventive film 2a is shaped onto the layer 4 through a thermal CVD (thermal chemical vapor deposition) method, a group II impurity is diffused selectively through a vacuum sealing method, and the Si3N4 diffusion preventive film 2a and the In0.53Ga0.47As layer 4 are gotten rid of. The In0.53Ga0.47 As layer 4 prevents the decomposition of InP or InGaAsP when the Si3N4 diffusion preventive film 2a is shaped through the thermal CVD method, and pinholes are hardly formed in the Si3N4 film 2a shaped through the thermal CVD method and even a thin film in approximately 500Angstrom displays a diffusion preventive effect. Accordingly, a group II impurity selective diffusion method to InP and InGaAsP capable of using the thin diffusion preventive film having few pinholes and little stress can be acquired.