Investigation of the potential of organic circuits for RFID tags

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Investigation of the potential of organic
circuits for RFID tags

• Qintao Zhang and Sha Li

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Matthias Handy
RFID-Workshop, 30.9./1.10.04, Berlin
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Organic transistors
Cgd0
Cgs0

• Organic tags are the only way of under-1-cent
  RFID tags

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Good and Bad things
Good things

• Flexible fabrication soluble materials can be
  printed on all kinds of material
• Transparent, important for display, may get
  e-paper, e-poster

Bad things

• No standard structures, L5mm10nm, Wseveral
  100um10mm, large overlap capacitance
• No standard semiconductor materials, Pentacene,
  P3HT, CuPc
• No Standard gate dielectric, K2 to 16
• No control of parameters, lots of different Vt
  reported
• fabrication limitation Cant shrink devices,
  typical number L2µm, W50µm for inkjet printing

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AIM-spice Model

• Good enough

Mobility 3cm2/VS Supply voltage 40V
Channel Length 2µm Contact resistance 7E5 ohm
Channel width 50µm
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Inverter


CMOS Inverter
Organic Inverter

• Complementary Static inverter

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Inverter
Pseudo-PMOS
Depletion Load PMOS
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Ring Oscillator
Wp/Wn1/1, Vdd40V, Freq394.42KHz,P490uW
Wp/Wn1/15, Vdd40V, Freq70.741KHz, P81uW

• Using Complementary inverter

Wp/Wn1/1, Vdd14.3V, Freq125.36KHz, P15.7uW
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Ring Oscillator
Depletion Load PMOS
Pseudo-PMOS
COMPLEMENTARY(15/1) PSEUDO DEPLETION
Tp (us) 14.136/2.535 10.8 74.4
Frequency (KHz) 70.741/394.42 92.593 13.44
Power (uW) 81.027/490.37 833.59 12.456
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NAND and NOR
Complementary NAND
Complementary NOR
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NAND and NOR
COMPLEMENTARY NAND COMPLEMENTARY NOR RATIO NAND DCVSL
Thl (us) 2.63/0.315 0.575/0.217 0.056 0.73
Tlh(us) 2.01/0.0899 1.61/0.191 0.025 0.026
Frequency (KHz) 380/3174.6 621.2/4608 17857 1370
Power (uW) 195/1.83 55.5/9.22 332 20.7
DCVSL
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Memory
NOR ROM
OR ROM NOR ROM
Tp (ns) 58.2 231
Frequency (MHz) 17.18 4.33
Power (uW) 250 256
OR ROM

• Mainly use P-type transistor in the ROM to
  improve the performance.

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Decoder
Decoder Wmin
Decoder Wp/Wn2/15
OR ROM DECODER DECODERROM
Tp (us) 0.0582 2.03 2.33
Frequency (KHz) 0.017 492.6 429.2
Power (uW) 250 31.8 407
Decoder OR ROM
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Conclusion

• Using current organic transistor technology, it
  is possible to run the RFID at 125KHz.
• Due to the big size of the device, the power
  consumption is much bigger than the regular CMOS
  circuit. This severely reduces the working
  distance of the organic RFID.