Water with surfactant:

To remove large particulates not strongly bonded to the surface, a surfactant (like soap or Tergitol) in DI water with ultrasonic agitation is effective at removing this type of dirt. Follow with running DI rinse.


Solvent with Ultrasound:

For some larger particles/organic residues, ultrasonic agitation in a solvent such as Acetone can work.


Wet Etchants:

Some particulates can be effectively oxidized and removed by strong oxidizers.

  1. RCA Clean (preferred process) (step 1 is enough for most of our work):
    a) NH4OH:H2O2:DI 1:1:5 at 80°C for > 5 minutes. Finish with a DI rinse.
    b) HCl:H2O2:DI  1:1:6 at 80°C for 5 minutes. DI rinse.
    Note: a) will etch GaAs
  2. Pirhana etch:
    a) H2SO4:H2O2 4:1 90°C for 10 minutes.
    b) DI rinse and dry.
    Note: a) will etch both GaAs and InP related compounds


Reference: See Chapter 2 of “ULSI Technology” by C.Y. Chang and S.M. Sze for further information.