Low-frequency noise of selectively dry-etch gate-recessed GaAs MESFETs

The authors report the input referred low-frequency noise (2-100 kHz) spectra of 0.2 μm-gate-length GaAs MESFETs which were gate-recess-etched using a selective Freon 12 based dry-etching process. For comparison, the noise spectra of nonselective wet-chemical, ammonia-based gate-recess-etched devices are also presented. Little change in low-frequency noise performance is observed for devices dry-etched for 30-50 s, demonstrating the latitude of the dry-etch process. Additionally, the input referred noise of the wet-etched devices was greater than that of 30, 40 and 50 s dry-etched devices, suggesting that the dry-etching process may passivate traps contributing to the low-frequency noise component of the MESFETs