Dear friends,

One of our current project here is to fabricate a simple lateral p-i-n
InGaAs photodiode.

In this project, we are attempting to fabricate a p-i-n InGaAs lateral
photodetector. One of the student is doing some simulation on it and at
the same time we're trying to study the fabrication process. However,
we're having some problem with the zinc diffusion step. We then attemp
to coat the InGaAs sample with spin-on zinc silica film on a blank
InGaAs sample. However, once the drive-in step is completed, we found
that the film starts to deteriorate. The zinc silica film are breaking
up into pieces (lots of cracking - unknown what they are). All the
fabrication are done according to the technical data sheet as provided
by the manufacturer (Emulsitone Inc).

Process steps:
Substrate:    InP(Fe)         Semi Insulating (S.I.)
Layer      :    In0.53 Ga0.47 As (undoped)    Thickness = 3um

Spin-on diffusion (zincsilicafilm 306)-    Spin 1: 500 rpm/5s-    Spin
2:  3000 rpm/30s    (Spin coater)
Post bake (120oC/15min)    (Hotplate)
Diffusion  in furnace (Zinc Drive in)-    Diffusion Temperature:
850oC-    Diffusion Time: 15 minute-    N2 environment (4500 sccm)
(Diffusion Furnace)
Dip in 10% HF    Zincsilicafilm remover

Best regards,
Abang Annuar Ehsan
Photonics Technology Lab
Institute of Micro Engineering and Nanoelectronics (IMEN)
Universiti Kebangsaan Malaysia
Bangi, Selangor, Malaysia