depositing a-Si

bwacker bwacker at
Sat Apr 10 07:37:54 PDT 2004

Amorphous silicon can be deposited in two ways, through LPCVD or PECVD.
Usually PECVD a-Si is more hydrogen rich. Hydrogen function is to passivate
silicon dangling bonds. It all matters when you use a-Si for devices and can
impact the transistor mobility for example. If you use LPCVD then at certain
combination of power and pressure (if higher pressure then lower
temperature) you will deposit a-Si. For example here at SNF you can use
Tystar tube to deposit a-Si at for 400mT and 560C or 570C. Also, LPCVD gives
you the advantage of using multiple substrates. Usually PECVD is a single
chamber deposition and also it's main purpose is to deposit on a large
substrate. I assumed that you want to deposit a-Si on Si or quartz
substrate. If you want to use a glass substrate then you certainly need to
look outside. I know that Xerox Palo Alto Research Center has a facility to
do that since they were once a world-wide leading group in the research on
a-Si:H but I do not know if they still do that for the outside customers.
You can always ask.

----- Original Message -----
From: "Vignesh G" <vigneshg at>
To: <labmembers at>
Sent: Friday, April 09, 2004 12:56 AM
Subject: depositing a-Si

> Hi all,
> I was told (by Mary Tang) that there was a company around about here
> somewhere which could deposit a-Si on substrates. Mary is away for the
> few days and I seem to have forgotten the name of that company. I was
> wondering if any of you would know of such a company. Thanks.
> - Vignesh.
> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
> Vignesh G. Shankar
> PhD Candidate in Materials Science and Engineering
> Stanford University
> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

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