1. Weekly Group Meeting Report
Renjie Chen
Supervisor: Prof. Shadi A. Dayeh

2. Summary
Starting from early last week, I was working on the Ni-InGaAs diffusion study. There are several problems faced when I start to repeat the process: failure of bonding, HSQ writing condition changes, and Cl-ICP etching condition shift.
My target was to: (1) Start with 3 set of new samples, make the bonding work
(2) Dose test for Fin writing with HSQ
(3) Modify Cl-ICP etching condition

3. Process of Ni-InGaAs Study
1st EBL - Markers
2nd EBL – Ni lines
3rd EBL – Fin
Plan
Anneal Temp
Fin Width
Time Sequence
220’C
20nm, 40nm, 60nm, 80nm, 100nm, 150nm, 200nm, 500nm
10min, 20min, 40min, 60min, 90min,120min
250’C
(repeat)
5min, 10min, 20min, 40min, 60min, 90min
280’C
2min, 5min, 10min, 20min, 40min, 60min
Diffusion

4. Dose Test for HSQ Recipe Surface Cleaning: Dip in CD30, 10min
Spin-coating: 6000rpm (2000rpm/s), 60s
Bake: 80’C for 4min
Developing: 80’C (measured to be 50’C) HDMS for 30s
Test parameters:
Writing Dosage: 750, 1000, 1250, 1500, 1750, 2000 uC/cm2
Directly on InGaAs surface & on Ni lines
One & two layers writing on Ni lines for protection
Room temperature & 80’C developing
Results:
No much difference of writing on Ni lines or directly on InGaAs
1750 uC/cm2 is good for one layer writing, 1250 uC/cm2 for 2 layers
Room temperature development gives more residuals
Current resolution of HSQ fin width ~ 28 nm

5. 750 uC/cm2
1 layer lines on Ni
750 uC/cm2
2 layer lines on Ni
1000 uC/cm2
1 layer lines on Ni
1000 uC/cm2
2 layer lines on Ni

6. 1250 uC/cm2
1 layer lines on Ni
1250 uC/cm2
2 layer lines on Ni
1500 uC/cm2
1 layer lines on Ni
1500 uC/cm2
2 layer lines on Ni

7. 1750 uC/cm2
1 layer lines on Ni
1750 uC/cm2
2 layer lines on Ni
2000 uC/cm2
1 layer lines on Ni
2000 uC/cm2
2 layer lines on Ni

8. Cl-ICP Etching Recipe Chamber Cleaning: 20min O2 plasma at 200W
Etching condition: 4 mTorr, ICP/RIE=230/30 W, Cl2/N2=2/20 sccm
Etching time: 105 s
ICP/RIE=230/30 W
ICP/RIE=230/50 W

9. Plan
Continue to finish the fabrication of the new set of Ni-InGaAs samples
-- EBL writing for Fin layer, followed by InGaAs dry etching and surface smoothing
-- RTA will be perform at two temperature and different time interval for these 12 samples
-- AFM will be used to measure the surface profile of the reacted Ni-InGaAs
-- Measure & plot the nickelide length with different fin width and reaction time
For achieving sub-10nm lines with HSQ
-- Mode 6 (lens 5) writing, writing filed will be 60um x 60um
-- dilute HSQ with MIBK
Fabricate the new set of neural probe samples with Ti/Ni/Ti/Ni metal stacking
-- Ti/Ni/Ti/Ni = 20/200/30/50 ?

10. Thank you Q&A