High performance heterojunction InGaAs/InP JFET grown by MOCVD using tertiarybutylphosphine (TBP)

A new InP-JFET (Heterojunction JFET or HJFET) having p/sup +/ GaInAs as the gate material is proposed and fabricated. The large valence band discontinuity in In/sub .53/Ga/sub .47/As/InP interface ( Delta E/sub V/ approximately=0.37 eV) considerably suppresses hole injection into the channel in this HJFET as compared to homojunction InP-JFETs, allowing higher positive gate bias without g/sub m/ compression. Heterojunction JFETs (HJFETs) with gate length of 0.6 mu m have resulted in a unity current gain cut-off frequency (f/sub T/) and power gain cut-off frequency (f/sub max/) of 14.3 GHz and 37.5 GHz, respectively. Using a self-aligned structure a g/sub m/ and f/sub T/ as high as 230 mS/mm and 21 GHz were obtained, respectively. At 4 GHz, a maximum power density of 1.0 W/mm with power added efficiency of 40% was obtained. These results indicate that the HJFET is a preferred device for high speed logic circuits based on JFET technology.<>