Ultra-flat InP substrates produced using a chemo-mechanical polishing technique

One of the factors that may control the ultimate performance of semiconductor opto-electronic devices is that of substrate flatness. This communication discussed the main principles involved in improving the flatness of wafers polished using chemo-mechanical techniques. Results are presented for the polishing of InP using a solution of bromine in methanol. At low bromine concentrations ( <1%) the micro-roughness of the surface was reduced to <1 nm over a lateral spacing of 25 μm.