B1.4 - Ultra-Thin Resistors for Piezoresistive Sensors
- SENSOR+TEST Conferences 2011
2011-06-07 - 2011-06-09
- Proceedings SENSOR 2011
- B1 - Piezoresistive Sensors
- B. Schmidt, M. Zier, P. Philipp - Helmholtz-Zentrum Dresden-Rossendorf e.V., J. Potfajova - VON ARDENNE Anlagentechnik GmbH, Dresden (Germany)
- 222 - 227
Piezoresistors in silicon has found applications in different kinds of sensors, for example in pressure sensors, accelerometers, multi-axis flow sensors and tactile sensor arrays. The emerging use of piezoresistive elements for deflection sensing of scanning probe cantilevers in Atomic Force Microscopy (AFM) is governed by efforts to overcome limited speed imaging and throughput using monolithically integrated arrays of AFM cantilevers. Consequently, to the integration of the detecting piezoresistive sensor, electro-thermal actuator integration into the cantilever compatible with modern CMOS processing has to be considered as fundamental for the realization of fast and large area high-resolution imaging.
The contribution describes shortly the fabrication of p-type silicon piezoresistive sensing and actuating resistive heater elements integrated in AFM cantilever arrays using ion implantation for doping of all elements including corresponding interconnecting lines between them. Because it has been predicted that for p-type piezoresistivity the values of the piezoresistive coefficients in ultra-shallow boron doped layers with a pn-junction depth < 10 nm can be approximately two times higher than in the p-type silicon bulk material special efforts are done for the realization of ultra-shallow boron profiles using different kinds of ion beam processing. The deflection sensitivity of selected ultrathin resistors has been measured and compared with conventional p-type silicon resistors.
Finally, technological challenges and problems at ultra-thin resistor fabrication and their integration in piezoresistive silicon sensors will be shortly discussed.