The $Si_3N_4$ deposition process by Remote Plasma Enhanced CVD(RPECVD) was developed and a 1∼8.6GHz GaAs broadband amplifier was designed and fabricated. The RPECVD deposited $Si_3N_4$ has dielectric constant range from 7.5 to 7.6 and its dielectric breakdown strength is about $3\times10^6$V/cm. The refractive index of $Si_3N_4$ ranges from 1.8 to 2.2 and its step coverage is good. Its application to MMIC was succesful.
The developed 1stage GaAs broadband amplifier with feedback cascode configuration has 7dB power gain over 1∼8.6GHz frequcncy range and its input and output VSWR are less than 2, 4 over bandwidth respectively. The active device of amplifier was the dual gate FET with $1\mu{m}$ gate length and $600\mu{m}$ gate width for both first gate and second gate.
