Optimization of two-layer resists for laser lithography on substrates required for wide application in microwave sensor technology

Abstract

We report on the optimization of laser lithography on various substrates relevant for ultra-high frequency on-chip experiments. We`re aiming at fabricating microstructured photoconductive switches for transport experiments with subpicosecond time resolution. Double layer resist systems for optimal lift-off processing of metal and semiconductor thin films are used. The double layer consist of LOR 3B as under layer and ma-P 1205 as top layer. Substrates are sapphire, i-GaAs, i-Si, SiO2 on i-Si, and SiO2 on p-doped Si. The target parameters for the optimization are the exposure dose and the edge roughness of microstructured elements. The latter is important to obtain high bandwidth striplines, microstrips, or coplanar waveguides.