Hi Finn,

There is no simple answer to your question. The piezoresistive
coefficient depend on the concentration, the doping species and the
crystal orientation just for mention a few. You have to look into the
literature and study the subject.

However, for boron doped piezoresistors in the <110> direction on
<100> silicon wafers the concentration are usually between 1E18 to
1E20 a/cm3, and the gauge factor between 100 and 10. But it will
strongly depend on your process.
(The gauge factor is defined as K=(dR/R)/strain)

regards
Gert Eriksen
---------------------------------------------------------------
Grundfos Semiconductor
Ryttermarken 15-21, 3520 Farum, Denmark
Tel.: +45 4434 7160 Fax: +45 4434 7172


On 1 Feb 2004 at 6:45, Finn Schixeon wrote:

> Hallo,
>
> I am building a silicon pressure sensor and the
> sensing mechanism is the use of piezoresistors.
>
> Is there any equation to determine how much doping of
> boron i need to create a piezoresistor of a certain
> piezoresistive coeeficient.
>
> If not is there a standard doping concentration for
> piezoresistors.
>
> Thanks
> Finn
>
>
>
>
>
>
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