Hi Ryu,

There are no issues with the deposition of amorphous silicon (a-Si:H) directly
on a glass substrate. Groups working with solar cells and thin film transistors
always deposit a-Si:H on a glass and plastic substrate. We in fact use it as a
structural layer for the MEMS and use glass as a substrate.

a-Si:H film deposited by you might be peeling off  because of the high stress in
the film. You will need to reduce the stress in the film by changing the
deposition parameters (Lowering RF power, chamber pressure or Silane flow).

regards,

Samadhan
www.inesc-mn.pt



        -----Original Message-----
        From: nz_overlander@yahoo.co.jp [mailto:nz_overlander@yahoo.co.jp]
        Sent: Thu 11/26/2009 12:39 PM
        To: mems-talk@memsnet.org
        Cc:
        Subject: [mems-talk] How to improve adhesion between aSi (by PECVD) on
glass



        Dear all,

        I want to improve adhesion amorphous Si film deposited by PECVD on the
        soda lime glass substrate.
        Now I wash the substrate by fuming HNO3 before CVD, but some of a-Si
        film is peeled off.

        So I'm going to try following approaches to improve adhesion,
        (1)Washing substrate by H2SO4-H2O2
        (2)Depositing Cr or Ti layer before a-Si CVD
        (3)Anodically bonding interface of a-Si film and substrate after CVD
        (not wafer to wafer bonding)

        In case of (2), I'm afraid of oxidation of Cr or Ti when carrying
        substrate from sputtering facility to CVD.
        In (3), there is no paper or report to improve adhesion with this
approach.

        If some of you have tried above approaches, will you tell me if it can
        go well or not?

        And does anybody know other approaches?

        thanks,
        Ryu