Cl2/Ar based inductively coupled plasma etching of GaN/AlGaN structure
2012
Cl 2 /Ar based inductively coupled plasma etching of GaN/AlGaN is investigated using photoresist mask in a restricted
domain of pressure < 10mTorr and RF power <100W, for selective mesa etching. The etch characteristics and rootmean-
square surface roughness are studied as a function of process parameters viz. process pressure, Cl 2 percentage in
total flow rate ratio, and RF bias at a constant ICP power, to achieve moderately high GaN etch rate with anisotropic
profiles and smooth surface morphology. The etch rate and resultant rms roughness of etched surface increased with
pressure mainly due to dominant reactant limited etch regime. The etch rate also increased with increasing Cl 2 % as a
result of increased chlorine radicals that enhances chemical etching. The etch rate and rms roughness showed strong
dependence on RF power with former increasing and later decreasing with applied RF power up to 80W. The
process etch yield variation with applied RF bias is also reported. Negligible etch selectivity was observed between GaN
and AlGaN up to 25% aluminum concentration with etch rate ~120nm/min. The studied etch parameters resulted in
highly anisotropic mesa structures with Ga rich etched surface.
Keywords:
- Correction
- Source
- Cite
- Save
- Machine Reading By IdeaReader
0
References
2
Citations
NaN
KQI