In <110> directions in the (100) plane:
G = E/[2(1+nu)] = 169 GPa/[2(1+0.064)] = 79.4 GPa.

In <100> directions in the (100) plane:
G = E/[2(1+nu)] = 130 GPa/[2(1+0.279)] = 50.8 GPa.

I think your software has confused the <100> and <110> directions.

> -----Original Message-----
> From: anant narain [mailto:[email protected]]
> Sent: Wednesday, September 26, 2001 12:25 PM
> To: Williams,Kirt (A-Labs)
> Subject: RE: [mems-talk] young's modulus,compliance coeff, poission
> ratio ofSi in <110> direction
>
> >
> dear sir,
> thanks for ur support.
> sir, i have one more confusion,
> what is value of shear modulus (G) of p-Si{100} along
> <110> direction.
> for <100> direction the values my software uses are
> G12=G13=G23=79.62 GPa , now i need to know these
> values along <110>.
> thanks,
> great regards,
> anant narain

>> --- [email protected] wrote:
> > Young's modulus E< 110> directions in (100) plane =
> > 169 GPa
> > Poissons' ration nu <110> directions in (100) plane
> > = 0.06
> > (this nu is unusually small,
> > but similar values have been reported by several
> > researchers).
> >
> > To calculate Young's modulus as a function of
> > direction, see
> > W. A. Brantley, "Calculated Elastic Constants for
> > Stress Problems associated
> > with Semiconductor Devices," J. Appl. Phys., v. 44,
> > no. 1, Jan. 1973, pp.
> > 534-544.
> > For graphs, see the curves in
> > J. Worthman and R. Evans, J. Appl. Phys., v. 36,
> > 1965, pp. 153-156.
> > These are reprinted in
> > Marc Madou, Fundamentals of Microfabrication, CRC
> > Press, Boca Raton, 1997,
> > p.161.
> >
> >             --Kirt Williams
> >
> > > -----Original Message-----
> > > From: anant narain [mailto:[email protected]]
> > > Sent: Monday, September 24, 2001 10:14 AM
> > > To: [email protected]
> > > Subject: [mems-talk] young's modulus,compliance
> > coeff, poission ratio
> > > ofSi in <110>direction
> > >
> > >
> > > hi!
> > >
> > > i am student doing M.Tech (microelectronics and
> > vlsi
> > > design) from I.I.T.Kharagpur,India.
> > > i am presently working in MEMS and developing a
> > > piezoresistive accelerometer.
> > >
> > > i wish to know the elastic constt. of Si in <110>
> > > direction specifically the Young's
> > modulus,poisson's
> > > ratio, and compliance coeff. along <110>
> > >
> > > thanks,
> > > great regards,
> > > anant narain
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