Oxford ICP Logbook
Notes:
- O2 Chamber cleans before etching is assumed but not strictly required, but if something goes wrong for your etch and you did not do an O2 clean beforehand, be sure to note this down.
- ICP etch rates can be highly nonlinear. Extrapolating to get an etch time for higher thicknesses may lead to over etch. Average etch rate (total etch depth/total etch time) can only be used for estimation.
- But, if this logbook goes long enough it might be possible to get a thickness vs etch time curve for certain materials, and we can have a better handle of our processes! (So, DO LOG YOUR RESULTS!)
| Date User | Sample & layer structure | Recipe name | Etch time | Etch depth (Dektak) | Notes |
|---|---|---|---|---|---|
2021-08-07 Yinan | B210416A (PECVD SiN @250C, 20min) | In Based 20 deg etch | 3min 20s | After removing SiN: | Seem like extremely over-etched. Stripped off the top absorber layer in lots of places, A rough-ish surface can be seen under Nomarski. |
2021-08-12 Yinan | GaAs Sac (PECVD SiN @250C, 20min) | In Based 20 deg etch | 2min 30s | Before removing SiN: 1000 nm (Dektak 6.5 um) After removing SiN: 850 nm (Dektak 6.5 um) | Avg Etch rate for (N-)GaAs = 340 nm/min Avg Etch rate for (250C) SiN = (380 - 150)/2.5 = 92 nm/min 380 nm (Dektak 6.5 um) SiN measured elsewhere. |
2021-08-12 Yinan | B210416A (PECVD SiN @250C, 20min) | In Based 20 deg etch | 2min 15s | Before removing SiN: 1070 nm (Dektak 6.5 um) (2021-08-16) After HCl dipsssss: 1280 nm (Dektak 6.5 um) | 380 - 92*2.25 = 173 1070-173 = 897 nm Supposedly down to GaAs, but the inner rim of the sample turned black-ish brown after a few minutes so probably near the end of the AlSb layer. (2021-08-16) seems like barely removed any AlSb at all? |
2021-08-23 Yinan | B210416A (PECVD SiN @250C, 20min) | In Based 20 deg etch | 3min 5s | After removing SiN: (need to measure on Dektak) | The majority of the surface looks gray and smooth after etch, but on the holey blocks, it looks bubbly. |
| test |