Development of direct ion-implanted gallium arsenide MESFET and low-actuation-voltage RF MEM switches

Over the past few years, multifunctional monolithic microwave/millimeter-wave integrated circuits (MMICs) have been developed and grown rapidly in the field of commercial wireless communication systems. The requirement of low-cost and high-performance MMICs made ion-implanted GaAs metal-semiconductor field effect transistors (MESFETs) one of the major workhorses of present digital and analog communication applications. In this work, the development of high-performance ion-implanted GaAs MESFETs will be presented. The fabricated device performance demonstrated a maximum f_T of 142 GHz and a maximum f_max of 235 GHz. In addition to the success of high-performance device development, the fabricated circuit results demonstrate the feasibility of GaAs MESFET in Ka-band and V-band circuits.; With the increasing demand for high-performance passive components, radio frequency (RF) microelectromechanical systems (MEMS)-based components have drawn much attention recently because of their excellent RF characteristics compared with conventional semiconductor-based counterparts. In this work, two novel topologies that enable low-voltage operation are proposed to address the need for monolithic integration with current MMICs and potential reliability issues. The developed fabrication processes are compatible with GaAs MMIC fabrication, and the fabricated devices demonstrated an excellent insertion loss of less than 0.1 dB and an isolation of better than 20 dB at a frequency of 40 GHz, along with a minimum operating voltage of less than 10 V for both switching topologies. The broadband frequency response and low insertion loss characteristics make RIF MEM switches the most important devices for reconfigurable circuit applications. Along with the low voltage characteristic, the RF MEM switches will be able to be monolithically integrated into current MMICs.; The high-performance GaAs MESFETs will provide a solution to low-cost NMCs, and the circuit results justify the readiness of this technology in Ka-band and V-band applications. The low operation-voltage switches will facilitate the direct integration with current MMICs and provide a solution to broadband reconfigurable circuits. The mature GaAs MESFET technology integrated with RF MEM switches will have a direct impact on RF circuit applications in the future.