Hello,
Does anyone know of any method by which one can get rid of any K+
ions from the Si- wafer , which has been anisotropically etched in KOH.
When anisotropic etching of Si was done using EDP etchant, removal of
traces of etchants was done successfully using RCA clean. However the
device design now needs a KOH etch (etch velocity ratio required is of the
order 1:400).
The reason why I am asking this question, is that at IIT Bombay,
there is a limitation of resources, and we have just one fabrication line.
This line is also used for CMOS fabrication. This enforces constraints in
process sequence,for MEMS related work like avoiding a thermal oxidation
after KOH etching of silicon.
Has anyone sucessfully prevented contamination of alkali metal
introduced by KOH etching, may be by washing it in ethanol/methanol ( 60%
: 40% v/v ) mixture (because of very high solubility).
Let me know even if anyone has attempted any cleaning process ( RCA,
methanol wash, ethanol wash, DI water wash.... ) and has it STILL CAUSED
contamination of K+ to persist. I am mentioning this is because we may
just be paranoid about contaminating our CMOS line and the K+ ions can
cleaned off in a process as simple as DI water wash.
Any answer's or speculations are wellcome.
Thank you ( in advance ) to those who would reply.
Regards
Amit Shiwalkar
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Amit Shiwalkar Dept. Of Bio-Medical Engineering.
3,Vasant, IIT Bombay.
Carter Road, Powai, Bombay-400076
Khar,
Bombay(Mumbai)-400052
INDIA.
Email: amits@cc.iitb.ernet.in
" Reality Is a Figment of IMAGINATION "
----------- Amit Shiwalkar
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