W-band InP/InGaAs/InP DHBT MMIC Power Amplifiers Yun Wei, Sangmin Lee, Sundararajan Krishnan, Mattias Dahlström, Miguel Urteaga, Mark Rodwell Department of Electrical and Computer Engineering, University.
Download ReportTranscript W-band InP/InGaAs/InP DHBT MMIC Power Amplifiers Yun Wei, Sangmin Lee, Sundararajan Krishnan, Mattias Dahlström, Miguel Urteaga, Mark Rodwell Department of Electrical and Computer Engineering, University.
W-band InP/InGaAs/InP DHBT MMIC Power Amplifiers Yun Wei, Sangmin Lee, Sundararajan Krishnan, Mattias Dahlström, Miguel Urteaga, Mark Rodwell Department of Electrical and Computer Engineering, University of California [email protected] tel: 805-893-8044, fax 805-893-3262 IMS2002 W-band MIMIC Power Amplifiers Y.C.Chen et. Al. IPRM, May 1999 2-stage 94 GHz W-band HEMT power amplifier 0.15 m composite-channel InP HEMT Imax=750mA, VBR=7V, Pout= 316 mW J. Guthrie et. Al, IPRM, May 2000 Cascode 78 GHz HBT power amplifier transferred substrate InGaAs/InAlAs SHBT Imax=100mA, VBR=2.5V, Pout= 12 mW This work single stage W-band HBT power amplifiers transferred substrate InP/InGaAs/InP DHBT Imax=128mA, VBR=7V, Pout= 40 mW Highest reported power for W-band HBT power amplifier Transferred-Substrate HBT MMIC technology HBT processing •Normal emitter and base processing no collector contact • polyimide isolation, SiN insulation, interconnection metals (M1 and M2), Benzocyclobutene planarization, thermal via and ground plane plating •Flip chip bounding to carrier •Substrate etching •Schottky contact collector simultaneous scaling of emitter and collector widths f max f / 8RbbCcb Wiring environment •Micro strip transmission line BCB dielectric, r=2.7, t=5 m •MIM capacitorsBCB bypass capacitor, SiN capacitor (r=7, t=0.4 m ) •NiCr resistor R=40/ Low via inductance, reduced fringing fields, increased conductor losses MBE DHBT layer structure InGaAs 1E19 Si 500 Å substrate Buffer layer 2500 Å collector Grade 1E16 Si 480 Å InP 2E18 Si 20 Å InP 1E16 Si 2500 Å Multiple stop etch layers base Grade 2E18 Be 67 Å InGaAs 4E19 Be 400 Å Band profile at Vbe=0.7 V, Vce=1.5 V emitter Grade 1E19 Si 200 Å InP 1E19 Si 900 Å InP 8E17 Si 300 Å Grade 8E17 Si 233 Å 400 Å InGaAs base 3000 Å InP collector 0.5 m Transferred-Substrate DHBT UCSB Sangmin Lee 40 fmax = 462 GHz, f = 139 GHz Gains (dB) 30 U 20 343 395 10 h21 139 462 0 1 10 100 1000 Frequency (GHz) BVCEO = 8 V at JE =0.4 mA/m2 Vce(sat) ~1 V at 1.8 mA/m2 6.0 2.0 5.0 Ic(mA) Ic(mA) 4.0 3.0 1.0 2.0 1.0 0.0 0.0 0 0.5 1 1.5 Vce(V) 2 2.5 3 0 1 2 3 4 5 Vce(V) 6 7 8 9 ARO MURI Multi-finger DHBTs: Design Challenges UCSB Thermal instability (current hogging) in multi-finger DHBTs: contact SiN emitter base poly collector BCB Metal strip Ic Ic Temperature Temperature BCB Au Via Steady state current and temperature distribution when thermally stable Thermal instability further increases current non-uniformity JAVce dVbe Stability factor K 1 to ensure uniform current distributi on dT R R kT / qI ex ballast E Distributed base feed resistance: Self-aligned base contact thickness=0.08 m base feed sheet resistance: s=0.3 /• Metal1 significant for > 8 um emitter finger length Emitter contact 0.08 m Base contact Large Area HBTs: big Ccb, small Rbb, even small excess Rbb substantially reduces fmax ARO MURI UCSB Large Current High Breakdown Voltage Broadband InP DHBT 2nd-level base feed metal 8-finger device 8 x ( 1 m x 16 m emitter ) 8 x ( 2 m x 20 m collector ) emitter 7 m emitter spacing ~8 Ohm ballast per emitter finger Flip chip fmax>330 GHz, Vbrceo>7 V, Jmax>1x105 A/cm2 collector Ballast resistor 30 140 A =128 um 120 25 U, MSG/MAG, dB 14 12 10 80 Ic, m A Ic, mA 100 60 8 6 4 40 2 0 -1 20 AE=128um2 2 E IC=100mA 20 15 Vcb=2.9V MSG/MAG U 10 5 0 1 2 3 4 5 6 fmax=330 GHz 7 Vcb, V 0 0 2 4 Vcb, V 6 8 10 0 0 10 10 1 10 2 Frequency, GHz 10 3 ARO MURI UCSB InP TS DHBT Power Amplifier Design • Designed using large signal model derived from DC-50 and 75-110 GHz measurements of previous generation devices Imax 0.018 0.016 0.014 • Shunt R-C network at output provides low frequency stabilization • Electromagnetic simulator (Agilent’s Momentum) was used to characterize passive elements 0.012 Ic (A) • Output tuning network loads the HBT in the optimum admittance for saturated output power 0.010 0.008 0.006 0.004 0.002 Low frequency stabilization Vsat 0.000 0.0 0.5 1.0 1.5 2.0 VCE_BR 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 Vce (V) Input match Optimum admittance match 7.0 ARO MURI UCSB W band 128 m2 power amplifier common base PA 0.5mm x 0.4 mm, AE=128 m2 Bias: Ic=78 mA, Vce=3.6 V 20 10 10 S21 GT 5 8 10 6 5 4 0 2 S11 -15 T -10 -20 -25 -30 80 90 frequency, GHz 100 110 G , dB -5 Pout, dBm S22 0 S11, S21, S22 Pout 15 -5 0 -15 -10 -5 0 5 10 Pin, dBm f0=85 GHz, BW3dB=28 GHz,GT=8.5 dB, P1dB=14.5 dBm, Psat=16dBm 15 ARO MURI UCSB W band 64 m2 power amplifier cascode PA bias 0.5mm x 0.4 mm, AE=64 m2 Bias condition: Ic=40 mA, Vce_CB=3.5 V, Vce_CE=1.5 V 15 15 S21 GT 5 Pout 8 Pout, dBm 10 0 -5 S22 -10 -15 6 GT, dB S11, S21, S22, dB 10 5 4 0 2 S11 -20 -25 10 80 90 100 frequency, GHz 110 -5 -15 -10 -5 0 5 Pin, dBm f0=90 GHz, BW3dB=20 GHz, GT=8.2 dB, P1dB=9.5 dBm, Psat=12.5 dBm 0 10 IMS2002 Conclusions UCSB • Wideband Power DHBT: Ic= 100 mA, Vce=3.6 V, fmax=330 GHz thermal design and base feed design critical for wide bandwidth • Power DHBT large signal modeling • Wideband Power amplifiers: f0=85 GHz, BW3dB=28 GHz,GT=8.5 dB, Psat=16dBm Future work • Higher power DHBTs: lumped 4-finger topology and longer emitter finger • Multi-stage wideband power amplifiers • ~200 GHz power amplifiers Acknowledgement Work funded by ARO-MURI program under contract number PC249806.