Effect of CVD - SiO2 film on reliability of GaAs MESFET with Ti/Pt/Au gate metal
The effect of CVD - SiO2 films on the reliability of GaAs MESFET with Ti/Pt/Au gate metal was investigated. It was found that the mean time to failure (MTTF) of MESFET with 350 degreesC-depositied SiO2 was only about one-seventh of that of the ones with 440 degreesC - SiO2. It was also found that, in the storage test at 300 degreesC for 24 hours, diffusion of Pt into GaAs was accelerated when the SiO2 deposition temperature was lower than 380 degreesC. FT-IR spectra indicated that the lower deposition temperature leads to a higher concentration of the residual hydrogen in SiO2. Thermal differential spectrometry (TDS) demonstrated that hydrogen in SiO2 could migrate even below 300 degreesC. In conclusion, the residual hydrogen in SiO2 causes the degradation phenomena.
cvd sio2 reliability gaas mesfet ti/pt/au gate hydrogen burn-in test