[mems-talk] Re: MEMS-talk Digest, What's the electrical resistance of bulk silicon wafer?

[imran ali]

Hello dear
   
  the formula for measure the resistance is as follows
  Resistance (R) = Rs(W/L),
  where Rs is sheet resistance is equal to resistivity of Sir(rho)/thickness of your junction.
   
  i hope it helps you.
   
  regards
  Imran Ali
  Pakistan
   

From: &#205;&#245;&#161;&#193;&#161;&#193; <bitmapcn at hotmail.com>
To: 'General MEMS discussion' <mems-talk at memsnet.org>
Date: Mon, 10 Dec 2007 16:54:52 +0800
Subject: [mems-talk] What's the electrical resistance of bulk silicon wafer?

Hi, all!

I plan to build some channels on <1 0 0> Silicon wafer by KOH etching.
Then I want to use Boron to dope part of the bottom of the channel.
The doped silicon has a feature size of 6um*100um and a thickness of 200nm.

I plan to use the doped silicon as a temperature sensor.
The resistance of the sensor in room temperature is of 10k Ohm order.

To measure the resistance of the doped area,
I need to apply voltage across the two ends.

My question is: what's the resistance of the Single crystal Silicon under my doped area?

The resistivity of my <1 0 0> Si wafer is around 10ohm-cm.
Calculation based on this gave me a resistance of the order of 100ohm for the 500um thick Si wafer under the doped area.
This is against my understanding of semiconductor material.

Can anyone help me with the estimation of the resistance of the bulk silicon wafer?
Thanks very much!