Collective fabrication of gallium-arsenide-based microsystems

GaAs is for many people regarded as being too difficult and expensive for a sensor or actuator application. It is a fact that GaAs is not cheap in comparison with silicon and also cannot currently be produced with as high purity and few crystalline defects as Si. Therefore, it is preferable to use GaAs where and when one can take advantage of the good properties that it possesses. Possible applications could be where high working-temperature, high frequency, integrated optoelectronics or piezoelectricity are demanded. As for silicon, gallium arsenide based microsystems should be manufactured on industrial production lines, with an additional post-processing for microsystem specific structures. Thus, using the same approach applied to silicon, CMP investigates gallium arsenide micromachining techniques using the Philips Microwave Limeil HEMT and the Vitesse MESFET foundry processes. This paper treats the advantages and disadvantages of gallium arsenide as a micromechanical material in comparison with silicon and quartz. The MESFET and HEMT compatible micromachining will also be detailed.