GaAs MEMS design using 0.2 /spl mu/m HEMT MMIC technology

This paper presents the GaAs front-side bulk micromachining using the 0.2 /spl mu/m HEMT MMIC technology from Philips Microwave Limeil (PML). The free-standing structures are obtained by removing wells of the GaAs substrate through an additional post-process wet chemical etching, without any modification in the standard IC fabrication and with no influence on the electronic behaviour. It is a very flexible approach to construct bridges, cantilevers and membranes. In respect to the suspended material and vertical profile, different structures could be realized according to the etching solution used and the layout arrangement. Among potential applications, thermopile based devices, such as infrared sensors, gas-flow sensors and thermoconverters could be targeted using GaAs/metal thermocouples. Moreover, suspended microstrips transmission lines and planar spiral inductor are also very useful to enhance the RF circuit performance. Finally, a complete CAD engineering kit containing the micromachining design rules, layout generators and a cross-section viewer has been developed on the Mentor Graphics framework.