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Wet Bench Germanium, wbgen2

The Wet Bench Germanium is for acid or base processing of Germanium wafers only

Picture and Location

 Wet Bench


The wbgen2 bench is currently dedicated to wet cleaning of Ge and Ge-containing substrates. 

Process Capabilities

Cleanliness Standard

The wbgen2 wet bench is in a special subcategory of the "Clean Equipment Group"
Wafers that have been processed in equipment outside of this equipment group may not be processed here.   Only Ge substrates and Ge-film containing substrates may be processed here. Materials control policies are governed by equipment groups; for the description of this policy, click <here>.
For equipment compatibility with specific materials, click <here>.

This wet bench is used before every critical furnace or deposition process. Therefore, perhaps more than any other station in the lab, it is absolutely imperative that procedures for proper handling and processing of materials be scrupulously observed, in order to minimize risk of contamination and thus minimize the potential for adversely affecting the research of other labmembers who use this equipment.

We ask that wbgen2 users to be very careful about their processing. We also recognize that occasional mistakes can happen, particularly in this dynamic research environment -- we only ask that wbgen2 users quickly report mistakes or accidents, so that staff can respond quickly to minimize any problem.


Clean Ge substrates and Ge-containing substrates.


Contact List and How to Become a User


See the Equipment Summary for the list of process and maintenance contacts for this station:


Ge Cleaning Procedure

Photoresist Strip:

  1. Resist strip – gasonics (044)
  2. Resist strip – wbgen2 (PRS-1000, 40ºC, 20min)
  3. Dump rinse/Spin-dry – wgben2 (twice)


Pre-Diffusion Clean:

  1. Organic clean – wgben2 (PRS-1000, 40ºC, 10min)
  2. Dump rinse/Spin-dry – wgben2 (twice)
  3. HF Dip (RT) – wgben2 (depends on protective LTO thickness)
  4. Cyclic HCl – wgben2 (thrice)
    1. 1min in 1:1 HCl:H2O (RT)
    2. Dump rinse
  1. Dump rinse/Spin-dry – wgben2


Maximum wait time between clean runs: 1 hour



NOTES: As far as cyclic HF procedure, see Sec. 3.1.2 Effective Native Oxide Removal (p. 57) in Jungyup Kim’s thesis.  According to XPS results, HF does not remove Ge sub-oxides while concentrated HCl (20%) does.  However, HF is necessary to remove the protective LTO layer that we typically deposit after Ge deposition.


NOTES: According to Jungyup’s thesis, HCl-treated Ge re-oxidizes within 10min.



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