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MEMS Technologies and Devices for Single-Chip RF Front-Ends



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MEMS Technologies and Devices for Single Chip RF Front Ends Clark T C Nguyen Dept of Electrical Engineering Computer Science University of Michigan Ann Arbor Michigan 48105 2122 CICMT 06 April 25 2006 C T C Nguyen MEMS Technologies and Devices for Single Chip RF Front Ends CICMT 06 4 25 06 Outline Motivation Miniaturization of Transceivers need for high Q merged transistor MEMS process High Q Vibrating Micromechanical Resonators clamped clamped beams micromechanical disks micromechanical circuits Low loss Micromechanical Switches Tunable C s and L s Conclusions C T C Nguyen MEMS Technologies and Devices for Single Chip RF Front Ends CICMT 06 4 25 06 Motivation Miniaturization of RF Front Ends RF RFPower Power Amplifier Amplifier Diplexer Diplexer 925 960MHz 925 960MHz RF RFSAW SAWFilter Filter 897 5 17 5MHz 897 5 17 5MHz RF RFSAW SAWFilter Filter 1805 1880MHz 1805 1880MHz RF RFSAW SAWFilter Filter Dual Band Dual BandZero IF Zero IF Transistor TransistorChip Chip 26 MHz 26 MHzXstal Xstal Oscillator Oscillator Problem Problem high Q high Qpassives passivespose poseaa bottleneck bottleneckagainst againstminiaturization miniaturization 3420 3840MHz 3420 3840MHz VCO VCO Antenna Mixer I LPF I A D Diplexer AGC 0o 90o Wireless Phone RF BPF LNA RF PLL RXRF LO Xstal Osc Q A D From TX Mixer Q C T C Nguyen MEMS Technologies and Devices for Single Chip RF Front Ends CICMT 06 4 25 06 LPF AGC Multi Band Wireless Handsets I Duplexer CDMA LNA RF BPF From TX Antenna RF BPF LPF 0o 90o RF BPF PCS 1900 I A D Q AGC GSM 900 LNA A D LPF Q I AGC LNA RF BPF DCS 1800 RXRF LO 0o 90o N 1 N LNA Duplexer CDMA 2000 Duplexer WCDMA RXRF Channel Select PLL RF BPF LNA From TX RF BPF LNA From TX Xstal Osc Q Tank The number of off chip high Q passives increases dramatically Need on chip high Q passives C T C Nguyen MEMS Technologies and Devices for Single Chip RF Front Ends CICMT 06 4 25 06 Surface Micromachining Fabrication steps compatible with planar IC processing C T C Nguyen MEMS Technologies and Devices for Single Chip RF Front Ends CICMT 06 4 25 06 Single Chip MEMS Transistor Integration Completely monolithic low phase noise high Q oscillator effectively an integrated crystal oscillator Oscilloscope Output Waveform Nguyen Howe Nguyen Howe 1993 JSSC 99 To allow the use of 600oC processing temperatures tungsten instead of aluminum is used for metallization C T C Nguyen MEMS Technologies and Devices for Single Chip RF Front Ends CICMT 06 4 25 06 Single Chip Integration RF RFPower Power Amplifier Amplifier Diplexer Diplexer 925 960MHz 925 960MHz RF RFSAW SAWFilter Filter 897 5 17 5MHz 897 5 17 5MHz RF RFSAW SAWFilter Filter 1805 1880MHz 1805 1880MHz RF RFSAW SAWFilter Filter Dual Band Dual BandZero IF Zero IF Transistor TransistorChip Chip 26 MHz 26 MHzXstal Xstal Oscillator Oscillator 3420 3840MHz 3420 3840MHz VCO VCO MEMS Technology Wrist watch sized Wrist watch sizedmulti band multi band wireless wirelessdevice devicemight mightbe bepossible possible C T C Nguyen MEMS Technologies and Devices for Single Chip RF Front Ends CICMT 06 4 25 06 Single Chip Transceiver All High Q Passives on a Single Chip 0 25 mm Vibrating VibratingResonator Resonator 1 5 GHz Q 12 000 1 5 GHz Q 12 000 GSM 900 RF Filter 935 960 MHz PCS 1900 RF Filter 1930 1990 MHz DCS 1800 RF Filter 1805 1880 MHz CDMA 2000 RF Filters 1850 1990 MHz WCDMA RF Filters 2110 2170 MHz C T C Nguyen MEMS Technologies and Devices for Single Chip RF Front Ends CICMT 06 4 25 06 m 0 5 m CDMA RF Filters 869 894 MHz Vibrating VibratingResonator Resonator 62 MHz Q 161 000 62 MHz Q 161 000 Optional RF Oscillator Ultra High Q Tanks Low Freq Reference Oscillator Ultra High Q Tank Thin Film Bulk Acoustic Resonator FBAR Piezoelectric membrane sandwiched by metal electrodes extensional mode vibration 1 8 to 7 GHz Q 500 1 500 dimensions on the order of 200 m for 1 6 GHz link individual FBAR s together in ladders to make filters h Agilent FBAR Limitations freq freq thickness thickness Q 500 1 500 TCf 18 35 ppm oC difficult to achieve several different freqs on a single chip C T C Nguyen MEMS Technologies and Devices for Single Chip RF Front Ends CICMT 06 4 25 06 Vibrating RF MEMS C T C Nguyen MEMS Technologies and Devices for Single Chip RF Front Ends CICMT 06 4 25 06 Basic Concept Scaling Guitar Strings Mechanical Resonator Vib Amplitude Guitar String Low Q High Q 110 Hz Freq Vibrating Vibrating A A String 110 String 110Hz Hz Stiffness Guitar Bannon et al JSSC 00 fo 8 5MHz Qvac 8 000 Qair 50 Freq Equation 1 kr fo 2 m r Freq Mass C T C Nguyen MEMS Technologies and Devices for Single Chip RF Front Ends CICMT 06 4 25 06 Performance Lr 40 8 m mr 10 13 kg Wr 8 m hr 2 m d 1000 VP 5V Press 70mTorr 1 51 GHz Q 11 555 Nanocrystalline Diamond Disk Mechanical Resonator Impedance mismatched stem for reduced anchor dissipation Operated in the 2nd radial contour mode Q 11 555 vacuum Q 10 100 air Design Performance Below 20 m diameter disk R 10 m t 2 2 m d 800 VP 7V Polysilicon Electrode CVD Diamond Mechanical Disk Resonator R Ground Plane Mixed Amplitude dB Polysilicon Stem Impedance Mismatched to Diamond Disk fo 1 51 GHz 2nd mode Q 11 555 84 86 88 90 92 94 fo 1 51 GHz Q 11 555 vac Q 10 100 air Q 10 100 air 96 98 100 1507 4 1507 6 1507 8 1508 1508 2 Frequency MHz Wang Butler Nguyen MEMS 04 C T C Nguyen MEMS Technologies and Devices for Single Chip RF Front Ends CICMT 06 4 25 06 Radial Contour Mode Disk Resonator Supporting Input Stem Electrode Output Electrode Q 10 000 Disk io v i R io vi VP C t Frequency Stiffness 1 fo 2 Young s Modulus kr mr E 1 R Density VP Note Note IfIfVVPP 0V 0V device deviceoff off dC io V P dt Smaller mass higher freq Smaller mass higher freq 13 e g m 10 13 kg Mass range and lower series Rx e g mr r 10 kg range C T C Nguyen MEMS Technologies and Devices for Single Chip RF Front Ends CICMT 06 4 25 06 and lower series Rx Multi Band Wireless Handsets I Duplexer CDMA LNA RF BPF From TX Antenna RF BPF LPF 0o 90o RF BPF PCS 1900 I A D Q AGC GSM 900 LNA A D LPF Q I AGC LNA RF BPF DCS 1800 RXRF LO 0o 90o N 1 N LNA Duplexer CDMA 2000 Duplexer WCDMA RXRF Channel Select PLL RF BPF LNA From TX RF BPF LNA From TX Xstal Osc Q Tank No Noneed needfor for switches switches C T C Nguyen MEMS Technologies and Devices for Single Chip RF Front Ends CICMT 06 4 25 06 Capacitively Capacitively transduced transduced micromechanical micromechanical resonators …


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