Process development of GaAs based RF MEMS

GaAs MMIC compatible process for RF MEMS Switch using 7-layered mask set has been developed. Semi- Insulating GaAs is used as substrate. E-beam evaporated 7000 A thick Ti/Pt/Au is used as bottom metal followed by 2.5 mu thick gold plating is used for CPW structure. PECVD nitride is used as field dielectric layer. Sputtered Au metal is used as a beam layer. Different sacrificial layers are tried and Polyimide was found to be good sacrificial layer to realise the air bridge structures. Different sizes of air bridge structures up to 320 microns length and 100 microns width were realised. SEM was extensively used for analyzing beam structure of different dimensions.