AW: [mems-talk] micro/macro Porous silicon formation

[Miyakawa, Natsuki]

Hi,

Have a look in the following review paper and dissertation:

- Formation and application of porous silicon, H.Foell, M, Christophersen, J.Carstensen, G.Hasse, Materials Science and Engineering R29 (2002) 93-141

- Untersuchungen zur Makroporenbildung in Silizium und deren technologischen Nutzung, M.Christophersen, 2002, Univ. Kiel, Germany

To 2.: the distincton between "acqueous" and "organic" seems to be based on the different I-V-characteristic. (see the paper)


Regards

Natsuki

-----Ursprüngliche Nachricht-----
Von: mems-talk-bounces at memsnet.org [mailto:mems-talk-bounces at memsnet.org] Im Auftrag von LSujatha
Gesendet: Mittwoch, 11. Juli 2007 05:47
An: mems-talk at memsnet.org
Betreff: [mems-talk] micro/macro Porous silicon formation

Dear friends,

Microporous is formed by electrochemical etching of silicon in HF+ethanol 
(aqueous electrolyte) on p-type (100)wafer with 1-10 ohm-cm resistivity. 

Macroporous is formed by electrochemical etching of silicon in HF+DMF
(Dimethyl formamide) (organic electrolyte) on the same wafer mentioned 
above. 

My questions are:

1. What is the theory behind for the formation of macroporous on p-type 
silicon with HF+DMF? i.e. Why is it macropores?

2. Why the electrolyte HF+ethanol is called aqueous and the electrolyte 
HF+DMF is called organic?