The reported gauge factor for p-type polysilicon piezoresistors is about
20-30 and for n-type piezoresistors is -20 to -25. Check these
references for further information:

V. A. Gridchin, V. M. Lubimsky, and M. P. Sarina, “Piezoresistive
properties of polysilicon films,” Sensors and Actuators A: Physical,
vol. 49, no. 1-2, pp. 67–72, June 1995.

P. J. French, “Polysilicon: a versatile material for microsystems,”
Sensors and Actuators A: Physical, vol. 99, no. 1-2, pp. 3–12, April 2002.

B. Bahreyni and C. Shafai, “Fabrication of piezoresistive sensors in
standard mems foundry processes,” in Proceedings of the 4th IEEE
Conference on Sensors, Irvine, USA, November 2005.

Good luck,
Behraad

> Subject:
> [mems-talk] Piezoresistance coefficients of polysilicon
> From:
> JOJI JOYKUTTY 
> Date:
> Tue, 17 Jan 2006 04:26:08 -0800 (PST)
> To:
> [email protected]
>
> Hello to all,
>   Can any one give me the values of piezoresistance coefficients of
polysilicon. Will it be the same as that of single crystal silicon??? I need the
values for some simulations. I would be very grateful if you can send me some
references which deal with the piezoresistive properties of polysilicon.
>   Waiting for a response.
>   Regards,
>   Joji