Dry Etching of Silicon Germanium in Fluorine RIE

Recipe

Gasses:

SF6

12.5 sccm

O2

2.5 sccm

He

10 sccm
Pressure1.0 Pa
RF Power40 W
Bias potential-115 W

Etch characteristics

Etch rate: 200 nm/min
Anisotropy: 80%

Selectivity

Etch rate of AZ 1420: 60 nm/min (selectivity: 3.3)

Remarks

Etch rate depends on substrate temperature
Etch rate depends strongly on Si/Ge ratio
Etch rate depends strongly on O2 content
Anisotropy depend strongly on O2 content
Poor reproducibility; requires proper conditioning of the reactor