MEMS resonators and their applications in timing circuits

Aarne OjaTikitin Ltd

26 April 2017www.tikitin.com

Email: aarne.oja@tikitin.com

MEF 2017, Tokyo, 2017

base station

Jack's phone

Frequency channels

Crystals and oscillators are everywhere in electronics

)2sin( ftp

fT 1=

ns 100MHz 10

==

Tf

Quarz resonator

Oscillator loopamplifier

Oscillator output signal

Quartz resonator dominate the market

Introduction to Tikitin Ltd

• Tikitin was established in May 2016 to commercialize the pioneering 17-yrs long research of MEMS resonator technology by the VTT Technical State Research Centre of Finland

• Mission: replace quartz crystals with MEMS resonators in time and frequency control applications

• Tikitin products• MEMS resonators (HighT & HighQ)• Core MEMS and a reference design for an Oven-Controlled MEMS

Oscillator (OCMO)• Entry markets: high-end markets• Go-to-market with strong partners

Production at a multi-user clean-room

• Tikitin uses the cleanroom of VTT Technical State Research Centre of Finland • 2600 m2 clean room with versatile tools for industrial MEMS manufacturing• Present capacity allows annual production up to 100 million MEMS resonators• No process transfer is needed when moving from R&D to production

Figure from VTT cleanroom http://www.micronova.fi/research/

Tikitin MEMS resonator technologies

Tikitin HighQ Resonator technology

• Electromechanical coupling by electrostatic force

• Narrow electrode gap needed• High bias voltage needed• Q = 1,000,000• Ideal for high-precision frequency control

applications

(Cross sections schematic, not to scale)

Tikitin HighT Resonator technology

• Electromechanical coupling by the thin-film AlN layer on top of the resonator

• Q = 10,000• Rm = 100 Ohm• Pin-to-pin replacement with quartz possible

Materials-based thermal compensation of Si resonators

Modified from A. Jaakkola et al, Proc. IEEE International Frequency Control Symposium, 2015, p. 420

Thin-film AlN MEMS resonator technology

Wafer-level packaging using eutectic bonding

Tikitin HighT Resonator technology

(Cross sections schematic, not to scale)

Thermal stability

• Frequency range 10 MHz … 50 MHz• Thermal stability of Tikitin HighT resonators better than that of AT-cut quartz

especially over a large operation range (up to 125 ∘C or 125 ∘C )• Even up to ±5 ppm over -45 ∘C … +85 ∘C

(Antti Jaakkola, Ph.D. Thesis 2016)

Size

• Tikitin HighT Resonator die footprint 800 µm x 700 µm • MEMS resonator thickness 400 µm

Samples available in June 2017Die size 1100 µm x 1100 µm x 650 µm

Phase noise

• Phase-noise performance similar to that of AT-cut quartz • Tikitin HighT MEMS resonators can be driven with several oscillator circuits

originally designed for quartz resonators (f.ex. NXP, Seiko, New Japan Radio, MAS)

-40-50-60-70-80-90

-100-110-120-130-140-150-160-170-1801101001k10k100k1M

Phaseno

ise[d

Bc/Hz]

FrequencyOffset[Hz]

25MHzQuartz

25MHzTikitinHighTHDMEMS

Value proposal for automotive applications

• High shock tolerance (about 20x better than with quartz)• Automotive AEC-Q200 certificate is business-as-usual for MEMS (but not for quartz)

(up to 125 deg-C but and above)• Tikitin HighT MEMS resonators have better temperature stability than quartz• External quartz resonator can be embedded within the sensor module such as tire-

pressure monitoring system (TPMS) similarly to the MEMS pressure sensor element• Sensor product owners are able to offer a more complete solution by increasing the

integration level• End customers can simplify their supply chain, save costs, and reduce risks

Illustrations from Infineon SP37 marketing material

MEMS for timing the IoT infrastructureRef Epsonhttp://www5.epsondevice.com/en/applications/wired_network/#05

MEMS opportunities in small cell base stations

• With deployment of 4g LTE and 5g, the number of base stations increases• Higher data rates and fan-less smaller base stations need frequency references which

operate at higher ambient temperatures (f.ex. up to +95 ∘C or above) • Small size and lower power consumption are also important• Tolerance against vibrations important for in-vehicle applications• High-quality-factor MEMS resonator Q ~ 1,000,000 suitable for precision applications• Key idea of an Oven-Controlled Oscillator: stay at the ”turn-over temperature” TTOT

Antti Jaakkola et al, Proc. IEEE International Frequency Control Symposium, 2014, p. 1

TTOT

Frequency vs temperature

MEMS resonators meet the OCXO performance level

• Ovenized Tikitin HighQ resonator shows a frequency stability better than 1 ppb/day

Oven-controlled MEMS oscillator (OCMO) value proposal

Feature Tikitin OCMO vs. state of art OCXO

Power consumption At least 4x lowerSize At least 3x smallerWarm-up time At least 15x fasterOperation temperature At least 10 deg-Celsius higher

No Freq.(MHz)

Aging Phase noise 1kHz offset (dBc/Hz) ref. 10 MHz

Volume(mm3)

Power(mW) at 25°C

Temp.coeff.(ppb/°C)

Warm-up time(sec)

1 Vendor1 Quartz OCXO

20 <±5 ppb/day -140 800 500 <±0.2 180

2 Vendor 2 Quartz OCXO

12.8 ±2 ppb/day (typ)

-145 313 400 <±1 180

3 Tikitin OCMO target specification

10 < 1 ppb/day -145 100 100 <±0.2 10

Important pioneering research by Stanford University, Carnegie Mellon University, and Sandia National Lab

The battle between Quartz vs. Si MEMS resonators

• Quartz resonators have been able to shrink and become cheaper• With the progress of “Looks like quartz MEMS resonator technology”,

MEMS offers a replacement opportunity practically in all product segments• Si MEMS should also have a cost advantage• Use of wafer-level-packaging (rather than ceramic packaging) brings

down the cost • Opportunity for a higher integration level (More than Moore) favors MEMS

• SiP• Heterogeneous integration (rebuilt wafer / e-WLP)• Monolithic integration• MEMS component clusters could make the entry into high-volume IoT

markets (f.ex. gyro + resonator)

Worldwide crystal and oscillator market is very fragmented –Will adoption of MEMS change the situation?

Tikitin value proposal & go-to-market strategy

• Tikitin is looking for strategic partnerships with (a few) industrial leaders in the frequency control market

• Tikitin offering to its partners• Unique MEMS resonators for selling & product branding• MEMS core and a reference design for an oven-controlled MEMS

oscillator• Partnership with Tikitin offers

• Differentiation with respect to competitors• Product diversification• Technology risk mitigation• Better satisfaction of customer needs

Summary

• MEMS resonators are starting to challenge quartz resonators in all commercially relevant product segments

• Benefits of Tikitin “Looks Like Quartz” technology include• Small size• Thermal stability• Mechanical robustness• Low aging

• Performance of oven-controlled reference oscillators can be taken to the next level by using MEMS

Samples available soon in limited quanities. Sign up if interested!