PLANAR INTEGRATION OF A RESONANT-TUNNELING DIODE WITH PHEMT USING A NOVEL PROTON IMPLANTATION TECHNIQUE

A novel technique of integrating resonant-tunneling diodes (RTD's) wit h pseudomorphic high-electron-mobility transistors (pHEMT's) is demons trated. A proton was implanted through the pHEMT layers to convert the RTD structure underneath to a high-resistivity buffer without degradi ng the performance of the pHEMT. The cutoff frequency is 16 GHz for a 1.5-mu m-gate-length pHEMT on such an implanted buffer. Substituting t he conventional deep mesa etch with ion implantation maintains a highl y planar surface, Such a monolithically integrated RTD/pHEMT oscillato r is described.