OPT application lab:
Cl2, CH4, H2, Ar process
10 µm deep InP/ InGaAsP etch

ICP - RIE schematic

OPT application lab:
Cl2, CH4, H2, Ar process
5 µm deep InP/ InGaAsP etch

process chemistry: Cl2, CH4, H2, Ar

rate > 1.5 µ/ min

selectivity > 15:1 to SiO2 or SiNx mask

uniformity < +/- 4 % (50 mm diameter)

excellent profile control

Plasmalab System 100
with loadlock and ICP180 source

Technology:

Reactive Ion Etching
with ICP Source (13 MHz)
Inductive Coupled Plasma
RF driven substrate electrode

OPT application lab:
Cl2/ N2 process
5 µm deep etch in InP/ InGaAsP

COMPARISON

The CH4/H2/Cl2 process does not need wafer clamping or a heated electrode, so it simplifies the hardware and allows the use of wafer pieces or batches of full wafers on a carrier plate.
The Cl2/N2 process offers a cleaner alternative, but requires a heated electrode and wafer clamping, i.e. only suitable for full wafers (or small pieces glued to a carrier wafer). The HBr process in addition offers the possibility of resist masked high rate InP etching.

OPT application lab:
HBr process
6 µm deep waveguide in InP/ InGaAsP

process chemistry: Cl2, N2

rate > 1 µ/ min

selectivity > 10:1 to SiO2 or SiNx mask

uniformity < +/- 4 % (50 mm diameter)

excellent profile control

System 100 cassette cluster

process chemistry: HBr

rate > 0.8 µ/ min

selectivity > 10:1 to SiO2 mask
PR mask possible !

uniformity < +/- 4 % (50 mm diameter)

good profile control