Gallium Nitride (GaN) is an important semiconductor material as GaN based devices have revolutionised the optoelectronics and high power electronics sectors. A great deal of attention has been focused on developing methods to fabricate semiconductor nanostructures with uniform size distributions. We report the formation of Excimer laser induced periodic surface structures. The ablation threshold of GaN with the 193 nm excimer laser was determined empirically. The surface structures were produced using a phase mask with a 668.2 nm periodicity. The features produced on the surface of the GaN were regular and of uniform periodicity, however, a significant amount of debris was generated during the machining of GaN. In order to try and reduce the debris generated further trials were carried out on both process optimisation and also on the use of a variety of assist gases. It is concluded that fluence does not have a significant impact on debris generation and Helium was found to be the most successful assist gas reducing the debris significantly.

1.
Yi
Zhou
et al, “
Formation, etching and electrical characterization of a thermally grown gallium oxide on the Ga-face of a bulk GaN substrate
”,
Solid State Electronics
52
(
2008
)
756
764
2.
P.E.
Dyer
,
R.J.
Farley
,
R.
Giedl
and
D.M.
Karnakis
, “
Excimer laser ablation of polymers and glasses for grating fabrication
”,
Applied Surface Science
96-98
(
1996
)
537
549
3.
M.D.
Ball
,
U.
Prendergast
,
C.
O’Connell
and
R.
Sherlock
, “
Comparison of cell interactions with laser machined micron-and nanoscale features in polymer
”,
Experimental and Molecular Pathology
82
(
2007
)
130
134
4.
P.E.
Dyer
,
R.J.
Farley
and
R.
Giedl
, “
Analysis of Grating Formation with Excimer-Laser Irraditated Phase Masks
”,
Applied Surface Science
96-98
(
1996
)
537
549
5.
Z.
Xiong
,
G.D.
Peng
,
B.
Wu
et al, “
Effects of the zeroth-order diffraction of a phase mask on Bragg gratings
”,
Journal of Lightwave Technology
17
(
1999
)
2361
2365
6.
P.E.
Dyer
,
R.J.
Farley
,
R.
Giedl
et al, “
Study and Analysis of Submicron-Period Grating Formation on Polymers Ablated Using KrF Laser Irradiated Phase Mask
”,
Applied Physics Letters
64
, (
1994
)
3389
3391
7.
M.K.
Kelly
,
O.
Ambacher
,
B.
Dahlheimer
,
G.
Groos
,
R.
Dimitrov
,
H.
Angerer
, and
M.
Stutzmann
, “
Optical Patterning of GaN Films
”,
Applied Physics Letters
69
(
2004
)
1749
8.
E.
Gu
,
M.D.
Dawson
,
H.
Howard
,
A.
Conneely
and
G.M.
O’Connor
, “
Microfabrication of Free-Standing Gallium Nitride using Laser Micromachining
”,
Applied Surface Science
252
(
2006
)
4897
4901
9.
J
Sun
and
J.P.
Longtin
, “
Inert Gas Beam Delivery for Ultrafast Laser Micromachining at Ambient Pressure
”,
Journal of Applied Physics
89-12
(
2001
)
8219
8224
10.
J
Sun
and
J.P.
Longtin
, “
Effects of a Gas Medium on Ultrafast Laser Beam Delivery and Materials Processing
”,
J.Opt.Soc.Am. B
, (
2004
)
1081
1088
11.
C.V.
Butz-Jorgensen
,
M.M.
Mund
,
B
Doggett
,
J.G.
Lunney
, “
Model for laser plume expansion in gas
”,
Journal of Physics D-Applied Physics
v39
(
2006
)
4739
4739
12.
C.J.
Knight
, “
Theoretical modelling of rapid surface vaporization and back pressure
”,
AIAA J.
17
(
1979
)
519
13.
M
Aden
,
E
Beyer
and
G
Herziger
, “
Laser-induced vaporisation of metals as a Riemann problem
”,
J.Phys.D: Appl Phys.
23
(
1990
)
655
61
14.
J
Arnold
and
F
Dausinger
, “
Surface structures produced by an Excimer laser during ablation of metals
”,
Proc. 3rd European Conference on Laser Treatment of Materials
,
Erlangen (ECLAT’90)
Vol
2
(
1990
)
859
15.
S.
Amoruso
,
J.
Schou
and
J.G.
Lunney
, “
Multiple-scattering effects in laser ablation plume propagation in gases
”,
Europhysics Letters
v76
(
2006
)
436
442
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