Dick Chang wrote:
>
>                                                                     9:07 AM
>   OFFICE MEMO                                                 Time:
>                       Subject:
>                       Mechanical Properties of SiNx, Au and...        6/26/96
>                                                               Date:
>
> Mr. Bolin:
>      I have found some Young's modulus values for SiNx, Au and Si thin films.
>
>      1. SiNx   290 nm thick,   Young's modulus: 222 (+/-) 3 GPa
>          Reference: J. J. Vlassak and W. D. Nix,  J. of Materials Research,
> Vol 7,          No.12 Dec 1992, pp3242-3249.
>      2. Au    0.87 micro-meter thick, Young's modulus 57 Gpa.
>      3. Si      Young's modulus 163 GPa
>          Reference for 2 and 3: William D. Nix, "Mechanical Properties of Thin
>                 Films," Metallurgical Transactions A, Vol. 20A, Nov. 1989, pp
> 2217-2245.
>
>      Also, please put my name on the distribution list of MEMS e-mail.
>      Thank you.
> Dick Chang
> Mechanics and Materials Technology Center
> The Aerospace Corporation
> (310)-336-5808
> e_mail: dick_chang@qmail2.aero.org
>
>

Silicon is an anisotropic material.  As a result the Young's Modulus
and Poisson's ratio change with direction in the material.