1. Bonding interface characterization devices
Option 2: Schottky diodes

2. Materials High resistivity epitaxial silicon Low resistivity silicon
High resistivity silicon wafer:
>5000 ohm.cm
Epitaxial layer thickness: around 20µm
Resistivity epitaxial layer: >1000 ohm.cm
Resistivity bulk silicon: 0.25 ohm.cm

3. Global view Legend Wafer before dicing Color Material
Low doped P-type silicon
Silicon dioxide
Bonding interface

4. Step 1: thermal oxidation
Wafer 1

5. Step 2: Temporary bonding
Carrier wafer
Wafer 1

6. Step 3: Thinning
Carrier wafer
Wafer 1
Swipe:
20µm
50µm
100µm

7. Step 4: covalent bonding
Carrier wafer
Wafer 1
Wafer 2
Instead of a standard high resistivity wafer, it is possible to use an epitaxial silicon wafer. This would avoid the need of ion implantation for ohmic contact.

8. Step 5: Temporary bonding release
Wafer 1
Wafer 2

9. Step 6: Cut in a 4’’ wafer shape

10. Steps to do at CMi SiO2 contact openings (front side)
Metal deposition for schottky contact (front side)
Metal deposition for ohmic contact (back side)