InGaAs/InP DHBTs demonstrating simultaneous ftau/fmax ~ 460/850 GHz in a refractory emitter process

Conference: IPRM 2011 - 23th International Conference on Indium Phosphide and Related Materials
05/22/2011 - 05/26/2011 at Berlin, Germany

Proceedings: IPRM 2011

Pages: 4Language: englishTyp: PDF

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Jain, Vibhor; Lobisser, Evan; Baraskar, Ashish; Thibeault, Brian J.; Rodwell, Mark J. W. (ECE Department, University of California, Santa Barbara, CA 93106-9560, USA)
Urteaga, M. (Teledyne Scientific & Imaging, Thousand Oaks, CA 91360, USA)
Loubychev, D.; Snyder, A.; Wu, Y.; Fastenau, J. M.; Liu, W. K. (IQE Inc., 119 Technology Drive, Bethlehem, PA 18015, USA)

We report InP/In0.53Ga0.47As/InP double heterojunction bipolar transistors (DHBTs) demonstrating simultaneous 460 GHz ftau and 850 GHz fmax. The devices were fabricated using a triple mesa process with dry-etched, refractory metals for emitter contact formation. The devices incorporate a 35 nm thick InP emitter which enables a wet etch emitter process demonstrating 220 nm wide emitter-base junctions with less than 10 nm undercut in the emitter semiconductor below emitter metal. This reduces the gap between base metal contact and emitter semiconductor causing significant reduction in emitter-base gap resistance (Rgap) component of the total base access resistance (Rbb), leading to an increase in observed fmax. At peak RF performance, the device is operating at 32 mW/µm2 with Je = 19.4 mA/µm2 and Vce = 1.66 V. The devices show a DC common emitter current gain (β) ~ 20 and VBR,CEO = 3.7 V.