SiGe BiCMOS and Photonic technologies for high frequency and communication applications Andreas Mai Department Head Technology
Outline Introduction & Motivation SiGe HBT device developments for high RF performance Optimization towards 700 GHz f MAX Electronic-Photonic-Integrated-Circuit (EPIC) SiGe-BiCMOS Integrated components, transmitter & receiver circuits Summary 2
THz SiGe HBT and BiCMOS
Motivation High-speed SiGe HBTs used today for: Automotive radar @ 24 GHz, 77 GHz and 120 GHz for transportation High data rate optical and wireless links Cut-off frequencies (f T, f max ) typically 3-10X larger than operating frequency Larger design margins, lower noise, higher gain, better linearity Lower power consumption 4
Motivation (cont) Further enhanced RF performance needed for potential new applications: Back-haul for 5G mobile comm. (optical or wireless) Short-range wireless links for high data rates mm and sub-mm wave imaging and sensing in medicine, industry, and science High-resolution sensors for robotics SiGe BiCMOS targets frequencies and data rates which are out of reach for state-of-the-art CMOS 5
European Projects on SiGe HBTs Enhancement of HBT performance and exploration of new application areas addressed DOTFIVE (2008-2011) Demonstration of HBTs with 500 GHz f MAX DOTSEVEN (2012-2016) Demonstration of HBTs with 700 GHz f MAX TARANTO (started 2017) BiCMOS platforms with 600 GHz f MAX targeting: Advanced automotive radar systems Infrastructure for 5G wireless and 400 Gb/s optical links 6
HBT Optimization & Process Modifications Starting point: IHP s 130nm BiCMOS SG13G2 Highly-doped collector isolated by STI Elevated extrinsic base Exploration of HBT performance limits irrespective of CMOS process constraints Starting Point SG13G2 Narrower Silicide Blocking Spacers Ni Silicide Final Status (D7) External Base Formation Scaled Emitter-Poly Width & Collector Window Millisecond Flash Annealing & Low-Temperature Backend [Heinemann, IEDM 2016] Reduced Width of Emitter & Emitter- Base Spacer SiGe Base Profile & Adjacent Low-Doped Emitter & Collector Region 7
Enhancement of f T and f MAX IEDM 16 IEDM 12 BCTM 09 Results of the DOT5 and DOT7 projects compared to IHPs 1 st generation 130nm BiCMOS 8
SiGe-HBT & BiCMOS performance evolution pre- Dot5 2004 2009 800 within Dot5 2009..2012 post Dot5 2012 today f max in GHz 700 600 500 400 300 200 100 IBM STM NXP Tower/Jazz IMEC Infineon IHP IEDM 2016 BCTM 2015 BCTM 2015 200 300 400 500 f in (GHz) T Successfully finished Simultaneously f T > 400 GHz and f max 700 GHz for discrete HBTachieved Advanced HBT module (~0.5 THz) integrated into 0.13µm BiCMOS process of IFX Demonstrator: 240 GHz RF chip-set + package (EuMW 16) 240 GHz radar transceiver + package + circular polarization (EuMC 15) 550 GHz full Si CT scanner (IRMMW-THz 16) 9
122GHz Radar as SiP and SoC ( SG13G2 == 0.5 THz SiGe-BiCMOS) SiP SoC System Requirements Frequency: 122-123 GHz ISM Pout: 0 dbm GT = GR: 10 dbi NF: 12 db BW: 1 GHz Modulation: CW/FMCW Distance: up to 5 meters On-chip integrated antenna by LBE process 10
Photonic-SiGe-BiCMOS (EPIC)
Silicon photonic transceivers Different market segments of optical/photonic area (telecom, automotive ) Requirements for continuous growth in bandwidth and IP traffic in optical networks, Long Haul and Metro applications Goal: Join basic components of e/o Transceiver (modulator, driver, amplifier, photo-detector,..) TRANCEIVER LASER PD Transmitter MODULATOR DRIVER Receiver AMPLIFIER Fiber-uplink Fiber-downlink Major application areas for SiPh tranceivers Metro Data center 12
Transceiver is a multi-chip assembly 13
Major silicon epic approaches/technologies (select.) Hybrid / Co-packaging Monolithic FEOL / CMOS Photonics Monolithic FEOL / Photonic BiCMOS FEOL = Front End of Line JS Orcutt et al.; OFC 2016 Photonic SOI CMOS IHP work Zero-change Photonic CMOS. Joint: CMOS + SiGe HBT + PIC G. Denoyer et al.; JLT 2015 14
Photonic BiCMOS 1st generation development goals 0.25µm RF-CMOS 5 ML / MIM SiGe HBTs 170GHz f T 200GHz f max 1.9V BV CEO SG25H4 BiCMOS baseline SG25H4_ePIC Ge-PDs (high bandwidth, resp.) MZI modulator 130nm node passives State-of-the-art Si-photonics 40+Gb/s Strict modularity of photonic integration Re-use of parent BiCMOS devices (models) No BiCMOS yield degradation Re-use of DigLib 15
Central for EPIC process integration Shared wafer Mixed Substrate: Localized SOI areas for optical structure Bulk like substrate for BiCMOS structures Common backend Modulized process flow Green: Active Red: Waveguide : STI Grey: local SOI 16
PIC- and EPIC-technology at IHP EPIC PIC 1. Mature 0.25µm-BiCMOS Technology available (SG25H4) 2. Development of PIC-process (Photonic Integrated Circuit) based on established 0.25µm-BiCMOS Technology (SG25_PIC) 3. Integration of PIC in BiCMOS EPIC (Electronic Photonic Integrated Circuit) (SG25H_EPIC) > 20 Layer > 10 Layer More than 30 Masks More than 700 process steps 17
EPIC Transmitters
Silicon cross section structuring 3 etching depths available: 220nm, 120nm, 70nm Vertical structuring is limited Freedom in horizontal structuring Dopings: p, n, p+, n+ wire waveguide Grating structures rib waveguide 19
Transmitters differ in phase shifter structure 4 Doped waveguide Depletion type MET3 MET2 MET1 TM1 BOX TM2 V-Pi*L [V*cm] alpha [db/cm] 3 2 0 1 2 3 4 5 6 7 8 12 11 Voltage [V] Injection type 10 0 1 2 3 4 5 6 7 8 Voltage [V] 20
integration Mach-Zehnder modulator segmentation Traveling wave electrode: Significant RF loss on the line Limited bandwidth and extinction ratio Velocity mismatch between optical and electrical waves Segmented MZM: Modulator divided into lumped segments Constant voltage along the phase shifter high ER Bandwidth expected to be less dependent on length longer phase shifters can be driven effectively with low driving voltage 21
1.3 mm Single MZM with linear driver 9.8 mm measurement ER=13.37 db 28 Gb /s simulation 1000 nm 500 nm 1640 nm 6 mm phase shifter divided into 16 segments ER=13.37 db Total fiber-to-fiber loss equal to 17 db (5 db from the phase shifter) Power dissipation equal to 2W or 71 pj/bit at 28 Gb/s EO bandwidth 18GHz D. Petousi et al, Monolithic Photonic BiCMOS Sub-System Comprising Broadband Linear Driver and Modulator Showing 13 db ER at 28 Gb/s, CLEO, 2016 22
2 mm MZM + driver with integrated DAC Concept:. Utilizing the segmentation of the modulator Integrated DAC resolution is limited due to layout and area constraints. With digital inputs, the driver is implemented as switching amplifier reducing power dissipation light in bit 0 bit 1 bit N-1 driver w/dac + MZM light out limiting amplifiers NO EXTERNAL DAC. 9 mm D. Petousi et al. High-Speed Monolithically Integrated Silicon Photonic Transmitters in 0.25 μm BiCMOS Platform. ECOC 2016. 23
Integrated Germanium photo diode Performance f 3dB >65GHz@-2V R>0.9A/W I dark <100nA@-1V VM2J_BW_0V M2J_BW_0V () _ () _ file: file: bias =0V, =1550nm EFA602_M2J_BW0V valid range: valid range: 0.41 0.41... 84.28... 84.28 valid: valid: 100.0% 100.0% wafer: wafer: EFA602-[06] ± mean 1s (lot): ± 1s (lot): 42.34 42.34 ± 2.10 ± 2.10 mean=42ghz ( =2GHz) dice: dice: 61 61 mean ± mean 1s (wafer): ± 1s (wafer): 42.34 42.34 ± 2.10 ± 2.10 Waveguide stub Metal1 contact invalid invalid > > 1 1 11 11 48.00 48.00 1 1 10 10 47.00 47.00 2 2 9 9 46.00 46.00 6 6 8 8 45.00 45.00 10 10 7 7 44.00 44.00 6 6 6 6 43.00 43.00 10 10 5 5 42.00 42.00 9 9 4 4 41.00 41.00 3 2 1 3 2 1 1 12 3 34 5 56 7 2 4 6 7 40.00 40.00 39.00 39.00 38.00 38.00 37.00 37.00 < < 15 1 15 1 Germanium photodiode building block invalid invalid class width class = width 1.00= 1.00 S. Lischke et al. Optics Express 23 (21), 2015 Jeong-Min Lee et al, Photodetection Frequency Response Characterization for High-Speed Ge-PD on Si with an Equivalent Circuit, WA2-78, OECC 2016 24
GePD: Benchmark Responsivity, e/o BW and dark current Fully integrated Ge PD in BiCMOS exceed performance level of discrete PD Enabler for high efficient Rx EPIC designs -1 V -2 V >-2 V 25
EPIC Circuit Examples
Recent results linear SP receiver Reference PD Extended BW (36GHz) Up to 56Gbps NRZ OOK 32 Gbps 40 Gbps 28Gbd PAM4 IHP Rx 48 Gbps 56 Gbps M. Kroh et al, Monolithic Photonic-Electronic Linear Direct Detection Receiver for 56Gbps OOK, ECOC 2016 27
Photonic BiCMOS evolution Demonstrators: monolithically integrated O/E RECEIVERS 2014 25 Gbps [Knoll et al., OFC 2014] 2015 40 Gbps [Awny et al., MWCL 2015] 56 Gbps 2016 Grating Coupler Ge PD TIA [ECOC2016 & ESSCIRC2016] 28
Photonic BiCMOS evolution Demonstrators: monolithically integrated E/O MODULATORS 10 Gbps 2013 [Zimmermann et al., ECOC 2013] HELIOS 2016 32 Gbps [Petousi et al., PTL 2016] 29
Summary Record values of f T =505 GHz, f MAX =720 GHz and t RO =1.34 ps demonstrated in an experimental SiGe HBT process Room for further improvements by lateral scaling EPIC technology developments show potential for beyond 100Gbit/s optical interfaces Ongoing challenging task of integrating these HBTs and Photonic modules in a BiCMOS platform 30
Acknowledgment IHP colleagues H. Rücker, B. Heinemann, D. Kissinger, H. Ng., L. Zimmermann, D. Knoll, S. Lischke, D. Petousi & M. Kroh IHP clean room staff Project partners and funding sources EU (H2020) & BMBF 31
Thank you for your attention! 32