Novel sub-quarter micron GaAs MESFET process with WSi sidewall gate

We have developed a novel sub-quarter micron WSi sidewall gate GaAs MESFET (SIG-FET) fabrication process. In this process, using WSi sidewalls as gate electrodes, the gate length is controlled only by the thickness of a WSi thin film deposited by DC sputtering and sub-quarter micron gates can be easily fabricated without using photo-lithography. The 0.15-μm-gate SIG-FET has exhibited gm_max = 360 mS/mm, f_t = 50 GHz and f_max = 120 GHz with Vth = -0.95 V. This novel process technology is very promising for fabricating high-performance sub-quarter micron gate MESFET's with low costs and high throughput.