1 N D I meeting G.Villani December,2010

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

3 In Vivo Dosimeter current 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 270° (ideally <30° off axes)  Fade effect due to thermal detrapping of charge approx 2%/20mins  1cGy 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 mm 20mm

4 RF UNIT POWER UNIT SENSING UNIT ELECTRONIC UNIT (VCO,TEMP COMP)  Proposed monolithic implantable In vivo dosimeter fabricated on the same silicon substrate  Smaller  Reliable  Cheaper  Fully integrated micro system < 1mm 3 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

5 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

6 V ~ 2.8mm 3 V ~ 69.2mm 3 Size comparison of the IVD.22 Long Rifle bullet Sicel IVD STFC IVD Proposed Monolithic In Vivo Dosimeter

7  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 Dosimeter summary Feasibility study of monolithic in vivo dosimeter: technologically possible Potential NDI activities:  development of [FG] MOS dosimetry for radiation monitoring

8 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 G K(X+Y) XY Low power readout

9 X Y Variation of the S-curve for the circuit of figure.. with change in floating gate NMOS threshold voltage. V th1 V th2 V th3 V th4 V th5 Low power readout

10 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

11 NMOS W=4;L=0.18 Floating Gate 10x10μm 2 SiO 2 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 5.3x5μm 2 Tunneling/Control Gate 0.3x0.2μm 2 PW 3.3x3μm 2 W contact FOX SiO 2 1μm Poly FG 5e19 DNW 2e17 IPW 2e17 Thin SiO 2 7nm Backup - IVD C- Flash process Radiation sensitivity:~ Vds = 2V, Qfg = -3fC DR ~ 1Gy (10x10μm 2 FG size)

12 Backup - IVD On chip ANT evaluation RF studies and on chip antenna fabrication W = 50W = B A set of antennas on chip are fabricated at MNTC (RAL) (PoC funding from Innovations, 2010) to evaluate achievable RF range The on chip antennas are then tested at RAL and UniBo 3