Abstract: A high power semiconductor device is formed by providing a semiconductor substrate of N.sup.- conductivity, rendering the backside of same porous as by subjecting same to anodic treatment carried out in a concentrated solution of hydrofluoric acid, converting the porous region to an N.sup.+ region, as by arsenic diffusion and forming an active device by conventional techniques in the top surface of the substrate. The method permits usage of high quality N.sup.- substrates and at the same time eliminates the requirement of growing thick epitaxial layers.

Abstract: A process for producing light emitting diodes is disclosed. In the process a primer layer of GaP is pyrolytically deposited on a Si substrate with the resulting epitaxial film thickness being sufficient to form complete coalescence of the epitaxial nuclei, but thin enough to avoid cracks in the epitaxial layer due to stress induced by thermal expansion. The thickness is generally between 0.1-10.mu.. A second layer of GaP is then deposited using the standard halide transport process with thicknesses of 2-5 .mu. or higher. In the case of GaP LED's the thickness is about 10-40 .mu., whereas for the case of GaAsP LED's the GaP thickness is 2-5 .mu. and this is then followed, through the addition of AsH.sub.3, with GaAsP graded from the GaP composition to the particularly desired design composition. The final composition is then maintained for 10-20 .mu..

Abstract: A high power semiconductor device is formed by providing a semiconductor substrate of N.sup.- conductivity, rendering the backside of same porous as by subjecting same to anodic treatment carried out in a concentrated solution of hydrofluoric acid, converting the porous region to an N.sup.+ region, as by arsenic diffusion and forming an active device by conventional techniques in the top surface of the substrate. The method permits usage of high quality N.sup.- substrates and at the same time eliminates the requirement of growing thick epitaxial layers.