Study Of GaAs HEMT-Embedded Accelerometer Structure And Process Design

Micro/nano-electro-mechanic System (MEMS) aim to enhance micromation, integration, explore devices and systems which are based on novel principle and new functions, open up a new technological field and industry. Due to defects in traditional detection methods of MEMS sensors, it is necessary to explore micro-mechanic structures based on novel principle and new functions to make breakthrough. High electron mobility transistors (HEMT) is one of field effect transistors, which is made by modulation doped heterostructure technology and possess super high electron mobility. When stress is applied for the channel, energy band structures of the HEMT will occur corresponding changes, which will affect the change of channel conductance. So it can fulfill high sensitive detection to the external parameter in proper working point.Based on the electromechanical coupling effect of GaAs HEMT structure, design, process methods and measurement et al of GaAs HEMT embedded accelerometer are studied in this paper. First,GaAs the HEMT thin film is designed and grown. Then the different dimensions of accelerometer have been design and analyzed by the software MATLAB; Meanwhile, the accelerometer has been simulated by ANSYS9.0 software. The process flow of the accelerometer based on the GaAs HEMT is established combining the process of micro-electronics and MEMS. Finally, The process integration of HEMT and MEMS is realized.The device parameter characteristics, temperature experiments, static pressure experiments, and dynamic experiments tests of the accelerometer are conducted. The measured results shows the sensitivity of the accelerometer is 10.68mV/g, and the frequency response less then 1000 Hz is relatively ideal. The innovations of this paper are First realization of sensitive detection to mechanical signal using HEMT at room temperature compared with traditional detection in china. It will be used in many appliances in the future. HEMT microelectronic technique and GaAs micromachining compatible processes is developed.