MEMS Folks,

  We are looking at purchasing a LPCVD system for surface
micromachining. I have done as much homework as I can (from papers and
the web), but I would like more upto date information.

 What we are looking for is a single system (i.e. 4 tubes) that we can
use for Poly Si surface micromachining. My questions are:

1) what chemistries are considered 'state of the art' for MEMS ? From
the literature, it looks like silane for poly Si and PSG/SiO2, and
dichlorosilane for SiN. Is this still considered the chemistries of
choice ? Also, are horizontal LPCVD furnaces stillthe machine of choice
?

2) How important is the choice of LPCVD system for producing films with
controlable stress and other mechanical properties ? Is there 'special'
control we need on an LPCVD system (as opposed to one used for MOS
devices) for MEMS (from a stress or uniformity perspective)

3) Who are some vendors that manufacture LPCVD system ? We are looking
for a machine aimed at the R and D market (1 to 25 wafer lots, 4"
wafers). I have some names and have talked to a few, but I want to be
complete.

4) What about using liquid sources for phosphorous doping (instead of
phosphine)? Is this being done ? Are there issues ?

5) Are there any emerging chemistries or materials we should make sure
we can handle ?

6) What about assoicated furnace needs. Is POCl necessary or can we get
away with solid diffusion sources for doping the surface of the Si ?
What are the concerns with POCL ? What about annealing ? Is this as
simple as it appears, or are does the tube need any special items ?

  Any suggestions are appreciated. Also, as always, anyone who wants
access to this inforamtion can e-mail me and I'll pass on the
inforamtion that I received.

   Thanks,
      Ken Westra
      Director, MicroFab at the University of Alberta