1 N D I meeting G.Villani December,2010. 2 Outline Dosimetry New low power solutions for RO based...

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1 N D I meeting G.Villani December,2010

Transcript of 1 N D I meeting G.Villani December,2010. 2 Outline Dosimetry New low power solutions for RO based...

Page 1: 1 N D I meeting G.Villani December,2010. 2 Outline  Dosimetry  New low power solutions for RO based upon LU effect  …

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N D I meetingG.Villani

December,2010

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Outline

Dosimetry New low power solutions for RO based upon LU effect …

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In Vivo Dosimetercurrent availability

IVD from Sicel: FDA clearance in 09 for use in breast and prostate radio treatment (clinical studies available) 0.4μm TOX MOSFET(RADFET) Hybrid design: separate RADFET ,readout and RF Power delivered via an external RF field, 15cm range Daily readings, unique 32bits tag 20 to 50mV/Gy sensitivity up to 80Gy ( non linear, individual device calibration, in the MeV range) Thermal sensor for calibration only; angular dependence up to 6% @ 270° (ideally <30° off axes) Fade effect due to thermal detrapping of charge approx 2%/20mins1cGy LSB, Total device errors ~ 5%, 2σ Operating frequency 133kHz, operating voltage of the implant 5V, backscattering technique (RFID tags)

An Implantable MOSFET Dosimeter for the Measurement of Radiation Dose in Tissue During Cancer Therapy , IEEE Sensor Journal, Vol. 8, No.1, Jan 08

2.1mm

20mm

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RF UNIT

POWERUNIT

SENSINGUNIT

ELECTRONIC UNIT

(VCO,TEMP COMP)

Proposed monolithic implantable In vivo dosimeter fabricated on the same silicon substrate Smaller Reliable Cheaper

Fully integrated micro system < 1mm3 includes radiation sensor, readout, power unit and RF unit to transmit data in the approved Medical Implant Communication Service band (MICS 402 – 405 MHz)

Standard communication band for future implantable devices

Radiation

RF receiver

Proposed Monolithic In Vivo Dosimeter

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Proposed Monolithic In Vivo Dosimeter

Low power electronic

Radiation Sensor Antenna

Layout Example of the proposed monolithic In vivo dosimeter CMOS technology 0.18μm allows integration of radiation sensors and RF, including antenna Power options include thin film battery on the back side or RF powering

1000μm

Thin film battery on the back side

Silicon chip

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V ~ 2.8mm3

V ~ 69.2mm3

Size comparison of the IVD

.22 Long Rifle bullet

Sicel IVD

STFC IVD

Proposed Monolithic In Vivo Dosimeter

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Studies and characterization of on chip micro antenna for wireless transmission in MICS band (PoC funding from Innovations Ltd.) CLASP proposal (Oct. 10) ~ 480K: report says ‘recommended for further CLASP support’ need to understand what it means

Feasibility study of monolithic in vivo dosimeter: technologically possible

Current activities:

Planned activities:

subject to positive CLASP outcome:• fabrication of monolithic test microdosimeter: radiation testing• interaction with commercial partners

In vivo Dosimetersummary

Feasibility study of monolithic in vivo dosimeter: technologically possible

Potential NDI activities:

development of [FG] MOS dosimetry for radiation monitoring

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Block diagram of a typical readout cell with typical power consumption per block.

Typical blocks found in a readout cell :Voltage follower, Charge amplifier, Shaper, Variable threshold comparator All these functional blocks could be implemented using a Latch up based readout

GK(X+Y)X

G

GKXY

1

Y

Low power readout

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PvsgNvgsNP gmgmRRG

X

Y

Variation of the S-curve for the circuit of figure .. with change in floating gate NMOS threshold voltage.

Vth1 Vth2 Vth3 Vth4 Vth5

Low power readout

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Initial studies: some interesting results, a couple of papers

No current activities: but probably justified in the context of generic R&D for new detector development

Tools and facilities required from NDI group:study and design efforts Equipment and tools already available

Low power readout - summary

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NMOS

W=4;L=0.18

Floating Gate 10x10μm2

SiO2

Substrate GND

D

S TG

Radiation sensor from a standard single poly CMOS process used for NVM memory

P Substrate 2e16

P++

FG P++

N++

TG

NW 5.3x5μm2

Tunneling/Control Gate

0.3x0.2μm2

PW 3.3x3μm2

W contact

FOX SiO2

1μm

Poly FG 5e19

DNW 2e17

IPW 2e17

Thin SiO2

7nm

Backup - IVD C- Flash process

Radiation sensitivity:~ 20mV/rad@ Vds = 2V, Qfg = -3fCDR ~ 1Gy (10x10μm2 FG size)

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Backup - IVD On chip ANT evaluation

RF studies and on chip antenna fabrication

950

950

11W = 50

150

950

22 B

A set of antennas on chip are fabricated at MNTC (RAL) (PoC funding from Innovations, 2010) to evaluate A set of antennas on chip are fabricated at MNTC (RAL) (PoC funding from Innovations, 2010) to evaluate achievable RF range achievable RF range

The on chip antennas are then tested at RAL and UniBoThe on chip antennas are then tested at RAL and UniBo

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