Isn't Si fairly transparent above 1.5 microns?

Marco
==============================================
Marc Reinig                           Phone: (831) 459-4362
Laboratory for Adaptive Optics        Fax:   (831) 459-5717
UCO/Lick Observatory                  Email: mreinig@ucolick.org
University of California, Santa Cruz
1156 High Street
Santa Cruz, CA 95064


> -----Original Message-----
> From: mems-talk-bounces+mreinig=ucolick.org@memsnet.org
> [mailto:mems-talk-bounces+mreinig=ucolick.org@memsnet.org] On Behalf
> Of Dean Hopkins
> Sent: Thursday, January 05, 2012 11:43 AM
> To: mems-talk@memsnet.org
> Subject: Re: [mems-talk] Optical absorbing material
>
> Hi Mike, would you consider "Black Silicon"?
>
> Anyone with a deep RIE system can treat your wafers to form a black
silicon
> 'grass' on horizontal exposed silicon surfaces. The black silicon process
is
> frequently used  in tuning the process for best vertical sidewalls.
>
> * High broadband optical absorption.
> I don't know the spectral range of absorption, but it is really black,
black,
> black.
>
> * Spin coatable.
> No, but is that a performance requirement or an artifact of the existing
> process sequence?
>
> *
>  Electrical resistivity as high as possible. As etched the 'grass' is
conductive,
> but a thin oxide or nitride layer can passivate it.
>
> *
>  Patternable.
> Simple. Only open the areas you want to blacken to the RIE.
>
> * Long life.
> As long lived as the silicon in the rest of the device.
>
> I think I might be able to intercede with a fab to get samples run, if you
are
> interested.
>
> Best,
>
> Dean Hopkins