A 0.5-mm InGaP Etch Stop Power pHEMT Process Utilizing Multi-Level High Density Interconnects
Walter A. Wohlmuth, Li Liu, Larry Witkowski, Rick Morton, Thorsten Saeger, Wolfgang Liebl, Mike Fredd, Domingo Farias, Wayne Sturble, Calvin Weichert, John Walkky, Steve Mahon, Otto Berger
Keywords: pHEMT, InGaP, BCB, D-mode
A robust and highly manufacturable InGaP etch stop pHEMT process with 0.5-mm gate lengths on 150 mm substrates is presented. The process utilizes a double recess approach to realize high breakdown, depletion-mode transistors with a nominal gate to drain breakdown voltage of 17 V. The transistors feature a nominal pinch-off voltage of -800 mV, on-resistance of 1.8 ohm-mm, extrinsic transconductance of 350 mS/mm, off-capacitance of 0.3 pF/mm, unity current gain cut-off frequency of 25 GHz, maximum frequency of oscillation of 90 GHz, and IDSS and IMAX values of 200 and 500 mA/mm, respectively. Passive components include precision 50 ohm/square NiCr resistor, 280 ohm/square epitaxial N-resistors, and 0.63 fF/um2 MIM capacitors. These devices are integrated with TriQuint’s high density, planarized, interconnect architecture enabling tremendous wiring flexibility and packaging simplicity. The interconnect structure utilizes benzocyclobutene (BCB) inter-metal dielectrics to form two levels of thick, global interconnects in addition to one level of local interconnect. This process, named TQPHT, is offered to external customers through TriQuint Foundry Services for a wide variety of applications including in part: high performance GSM, CDMA, and WLAN switches, medium power amplifiers, and low-noise amplifiers.