Measurement and Modeling of CMOS Devices in Short Millimeter Wave. Minoru Fujishima

Transcription

1 Measurement and Modeling of CMOS Devices in Short Millimeter Wave Minoru Fujishima

2 Our position We are circuit designers. Our final target is not device modeling, but chip demonstration. Provided device model, if any, is acceptable for us. Our approach may not be academic nor deeply considered from physical insight, but pragmatic for our target. Today s presentation is our requisite device modeling in short-millimeter-wave region. From the next slide, our position for designing millimeter-wave CMOS circuit will be explained. 2012/9/21 MOS-AK 2

3 2012/9/21 MOS-AK 3 Chip Development Process Goal of modeling experts Device Circuit System Measurement Our goal

4 2012/9/21 MOS-AK 4 General Analog/RF Designers Starting point of circuit designer Designers assume it is device engineers duty Device Circuit System Measurement

5 2012/9/21 MOS-AK 5 For Millimeter-Wave Designers Customization for millimeter-wave region (DC model is provided from foundry.) Device Circuit System Measurement We have to complete every layers.

6 2012/9/21 MOS-AK 6 Millimeter-Wave Design Device Circuit System Measurement

7 2012/9/21 MOS-AK 7 Bond-Based Design Use Device Tiles MOSFET Transmission Line Pad etc. Interface for tiles Transmission Line No Parasitic Wire Connect No LPE is required

8 2012/9/21 MOS-AK 8 Millimeter-Wave Design Device Circuit System Measurement

9 2012/9/21 MOS-AK 9 Accurate Probing TL4 TL6 THRU By utilizing scotch tape marker, probing positions are well controlled.

10 2011/12/9 IEEE SSCS DL seminar 10 Millimeter-Wave Design Device Circuit System Measurement will be explained later

11 2012/9/21 MOS-AK 11 Millimeter-Wave Design Device Circuit System Measurement

12 Wideband 140GHz CMOS Amp. 63µ 17µ 72fF L/W of MOSFET = 65nm / 22.6µm Transmission line unit : m 112µ 41µ M2 56µ M3 56µ M4 27µ M5 60µ M6 26µ M7 410µ 126µ 21µ M1 126µ 17µ 23µ 42µ 40µ 26µ 23µ 27µ 17µ 27µ 60µ 174µ Input Output 2012/9/21 MOS-AK 12

13 Measurement Results Freq. [GHz] 0.1dB-BW [GHz] 3dB-BW [GHz] Gain [db] Group Delay [ps] Peak Gain [db] Gain [db] Frequency [GHz] [ps] P DC [mw] 12GHz Technology [nm] ± Specification Summary Frequency Characteristics 0.1dB Frequency [GHz] 2012/9/21 MOS-AK 13

14 2012/9/21 MOS-AK 14 Millimeter-Wave Design Device Circuit System Measurement

15 2012/9/21 MOS-AK GHzCMOS Wireless TRx Chips Set RFin BBout LNA DET Limiting Amp. Buf. TX PA-free Tx RX Fabricated with 40nm CMOS process TRx total power consumption: 10Gbps/98.4mW(9.8pJ/bit) Demonstration of 10cm transmission VLSI Symposium 2012

16 2012/9/21 MOS-AK 16 Millimeter-Wave Design Device Circuit System Measurement

17 2012/9/21 MOS-AK 17 Accuracy of PDK model in D band S 11 S G 130G 150G 170G S 21 S G 130G 150G 170G

18 Sub-Circuit Extension Parasitic component to be extracted Provided MOSFET model from PDK 2012/9/21 MOS-AK 18

19 2012/9/21 MOS-AK 19 Accuracy of sub-circuit extention S 11 S G 130G 150G 170G S 21 S G 130G 150G 170G

20 2012/9/21 MOS-AK 20 Circuit and Layout Diagram of LNA Cascode Amplifier 65nm-CMOS technology Tiles for MOSFETs, transmission lines and pads are used

21 2012/9/21 MOS-AK 21 Measured and Simulated Results S 11 S G 130G 150G 170G S 21 S G 130G 150G 170G Gain at 120GHz Simulated : -4.3 db Measured : -4.9 db Difference : 0.6dB

22 2012/9/21 MOS-AK 22 Issues in S 11 and S 22 Sub-circuit extension C m Measurement Measurement Our model Our model S11 S22 L l L r port1 C l C r port2 provided MOSFET model Sub-circuit topology is firstly decided. Parasitic elements are extracted to fit a measured result including the provided model. Reflections of the scattering parameters of this model (S 11, S 22 ). This model cannot trace all frequencies due to fixed topology.

23 2012/9/21 MOS-AK 23 Problems of Conventional Way Applicable frequency range is limited. All S 11, S 12, S 21, S 22 are difficult to fit simultaneously. Voltage dependency of parasitic elements is not considered. All the physical model in short millimeter wave is not considered. For example: Non-quasi-static (NQS) effect Vgs Id

24 Solution: Matrix-based Model From PDK From measurement Provided I-V model with parasitic C s ac simulation Frequency-dependent admittance matrix S parameters obtained from VNA. S to Y transformation Frequency-dependent admittance matrix differentiated No equivalent circuit is assumed Admittance-wrapper model (Y-wrapper model) 2012/9/21 MOS-AK 24

25 2012/9/21 MOS-AK 25 Provided Model and Measured Data Measured admittance of a device Y meas Extracted elements in admittance region ground MOSFET device ground Y wrap distinguish port1 port2 port1 port2 ground ground Y logic provided model of MOSFET in admittance region Y wrap = Y meas Y logic

26 2012/9/21 MOS-AK 26 Equivalent Circuit y in = y11 + y12 yreverse = y12, y forward = y21, yout = y22 +, y 21 i 1 V gs V ds Y wrap i 2 port1 v 1 y in (v gs ) y reverse (v gs ) y forward (v gs ) y out (v gs ) v 2 port2 v 2 Y logic v 1 Equivalent circuit with four branches. After Y-wrapper matrix is extracted, equivalent circuit is determined.

27 2012/9/21 MOS-AK 27 Non-Quasi-Static (NQS) Effect i 1 i V Y 2 gs V ds wrap port1 v 1 y in (v gs ) y reverse (v gs ) y forward (v gs ) y out (v gs ) v 2 port2 v 2 Y logic v 1 y12 and y21 are modeled (wrapped) independently. Even if high-frequency (non-quasi-static: NQS) gm is not considered in the provided model, this wrapper can cover special effects in short millimeter wave.

28 2012/9/21 MOS-AK 28 Voltage Dependence of Parasitics Im {y 11 } [ms] Im {y 21 } [ms] GHz Measurement 60GHz 20GHz 100GHz Measurement 60GHz 20GHz Im {y 12 } [ms] Im {y 22 } [ms] GHz Measurement 60GHz 20GHz Measurement 100GHz 60GHz 20GHz V gs [V] V gs [V]

29 2012/9/21 MOS-AK 29 Bench Mark with Common-Source Amp. One-stage common-source amplifier to verify the Y-wrapper model. MOSFET Capacitor Y-wrapper model of MOSFET ground in ground ground out ground in 71.1μm 100.6μm 31.2μm 101.5μm W/L = 32μm/44nm 73.7μm 55.8μm 75fF out Capacitor bias ground vdd bias Transmission lines vdd A pair of matching networks, which are made of transmission lines, are connected to a MOSFET whose gate bias and vdd are fed via the matching networks.

30 2012/9/21 MOS-AK 30 Measurement and Y-wrapper Model 10 S-parameter [db] bias = 0.0V vdd = 1.1V bias = 0.6V vdd = 1.1V S11 S-parameter [db] bias = 0.8V vdd = 1.1V Frequency [GHz] bias = 1.1V vdd = 1.1V Frequency [GHz] S12 S21 S22

31 2012/9/21 MOS-AK 31 Conclusion Millimeter-wave designers generally have to provide device model by themselves. Provided PDK can be improved for shortmillimeter-wave circuit design. But general subcircuit extension is not sufficient for shortmillimeter wave. Matrix-based Y-wrapper can include NQS effect, and is demonstrated for short-millimeter-wave model.