Plasma Technology  

OPT application lab:
anisotropic AlGaN/ GaN etch
stopping in the saphire substrate

OPT application lab
sloped 2µm deep GaN etch at 1.5 µm/ min
(ca 1:1 selectivity to PR)

GaN ICP Etching


Reactive Ion Etching
with ICP Source (13.56 MHz)
Inductive Coupled Plasma
13.56 MHz Plasma Excitation
Process chemistry: Cl based
RF driven substrate electrode

Rate : 0.15 - 1.5µm/ min
Selectivity to SiO2 mask 8 - 15 : 1
Selectivity to Ni mask 30 : 1
Selectivity to PR mask 0.7 - 1.1 : 1
very uniform process
anisotropic profile
smooth etched sidewalls suitable for
laser facet formation
Sloped profile by PR erosion


ICP schematic


PlasmaPro 100:
with ICP source

OPT application lab
sloped 3 µm deep GaN etch at 2 µm/ min
(ca 1:1 selectivity to PR)


OPT Application lab:
mini Marathon with 200 wafers

Average GaN etch rate = 1.76µm/min
Cross wafer uniformity < ±3% at small EE
Run to run uniformity ± 1.5%
Average Selectivity GaN: PR = 1.10:1

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