In this paper, the femtosecond laser ablation of silicon is investigated by a two-dimensional hydrodynamic model. The ablation depth of the silicon wafer ablated in air at different laser intensities is calculated, and the corresponding experimental measurements are carried out for validation. Two different ablation regimes have been identified by varying the laser fluence. While two-photon absorption dominates in the low fluence regime (<2 J/cm2), electron heat diffusion is a major energy transport mechanism at higher laser fluences (>2 J/cm2). The ablation efficiency first increases with the laser fluence, and reaches the peak value at the laser fluence around 8 J/cm2. It starts to drop when the laser fluence further increases, because of the early plasma absorption of the laser beam energy.

References

References
1.
Momma
,
C.
,
Nolte
,
S.
,
Chichkov
,
B. N.
,
Alvensleben
,
F. V.
, and
Tünnermann
,
A.
,
1997
, “
Precise Laser Ablation With Ultrashort Pulses
,”
Appl. Surf. Sci.
,
109/110
, pp.
15
19
.10.1016/S0169-4332(96)00613-7
2.
Furusawa
,
K.
,
Takahashi
,
K.
,
Kumagai
,
H.
,
Midorikawa
,
K.
, and
Obara
,
M.
,
1999
, “
Ablation Characteristics of Au, Ag, and Cu Metals Using a Femtosecond Ti:Sapphire Laser
,”
Appl. Phys. A
,
69
, pp.
S359
S366
.10.1007/s003390051417
3.
Oh
,
B.
,
Kim
,
D.
,
Kim
,
J.
, and
Lee
,
J.
,
2007
, “
Femtosecond Laser Ablation of Metals and Crater Formation by Phase Explosion in the High Fluence Regime
,”
J. Phys.: Conf. Ser.
,
59
, pp.
567
570
.10.1088/1742-6596/59/1/121
4.
Nolte
,
S.
,
Momma
,
C.
,
Jacobs
,
H.
, and
Tünnermann
,
A.
,
1997
, “
Ablation of Metals by Ultrashort Laser Pulses
,”
J. Opt. Soc. Am. B
,
14
(
10
), pp.
2716
2722
.10.1364/JOSAB.14.002716
5.
Ahn
,
S.
,
Hwang
,
D. J.
,
Park
,
H. K.
, and
Grigoropoulos
,
C. P.
,
2012
, “
Femtosecond Laser Drilling of Crystalline and Multicrystalline Silicon for Advanced Solar Cell Fabrication
,”
Appl. Phys. A
,
108
, pp.
113
120
.10.1007/s00339-012-6932-4
6.
Lee
,
S.
,
Yang
,
D.
, and
Nikumb
,
S.
,
2008
, “
Femtosecond Laser Micromilling of Si Wafers
,”
Appl. Surf. Sci.
,
254
, pp.
2996
3005
.10.1016/j.apsusc.2007.10.063
7.
Bellouard
,
Y.
,
Said
,
A.
,
Dugan
,
M.
, and
Bado
,
P.
,
2004
, “
Fabrication of High Aspect Ratio, Micro-Fluidic Channels and Tunnels Using Femtosecond Laser Pulses and Chemical Etching
,”
Opt. Express
,
12
, pp.
2120
2129
.10.1364/OPEX.12.002120
8.
Zhao
,
X.
, and
Shin
,
Y. C.
,
2011
, “
Femtosecond Laser Drilling of High-Aspect Ratio Microchannels in Glass
,”
Appl. Phys. A
,
104
, pp.
713
719
.10.1007/s00339-011-6326-z
9.
Zhao
,
X.
, and
Shin
,
Y. C.
,
2012
, “
A Two-Dimensional Comprehensive Hydrodynamic Model for Femtosecond Laser Pulse Interaction With Metals
,”
J. Phys. D: Appl. Phys.
,
45
(
10
), p.
105201
.10.1088/0022-3727/45/10/105201
10.
Wu
,
B.
, and
Shin
,
Y. C.
,
2007
, “
A Simple Model for High Fluence Ultra-Short Pulsed Laser Metal Ablation
,”
Appl. Surf. Sci.
,
253
, pp.
4079
4084
.10.1016/j.apsusc.2006.09.007
11.
Qiu
,
T. Q.
, and
Tien
,
C. L.
,
1993
, “
Heat Transfer Mechanisms During Short-Pulse Laser Heating of Metals
,”
ASME J. Heat Transfer
,
115
, pp.
835
841
.10.1115/1.2911377
12.
Mao
,
S. S.
,
Mao
,
X.
,
Greif
,
R.
, and
Russo
,
R. E.
,
1998
, “
Simulation of Infrared Picosecond Laser-Induced Electron Emission From Semiconductors
,”
Appl. Surf. Sci.
,
127
, pp.
206
211
.10.1016/S0169-4332(97)00633-8
13.
Bulgakova
,
N. M.
,
Stoianm
,
R.
,
Rosenfeld
,
A.
,
Hertel
,
I. V.
, and
Campbell
,
E. E. B.
,
2004
, “
Electronic Transport and Consequences for Material Removal in Ultrafast Pulsed Laser Ablation of Materials
,”
Phys. Rev. B
,
69
, p.
054102
.10.1103/PhysRevB.69.054102
14.
Bulgakova
,
N. M.
,
Stoian
,
R.
,
Rosenfeld
,
A.
,
Hertel
,
I. V.
,
Marine
,
W.
, and
Campbell
,
E. E. B.
,
2005
, “
A General Continuum Approach to Describe Fast Electronic Transport in Pulsed Laser Irradiated Materials: The Problem of Coulomb Explosion
,”
Appl. Phys. A
,
81
, pp.
345
356
.10.1007/s00339-005-3242-0
15.
Van Driel
,
H. M.
,
1987
, “
Kinetics of High-Density Plasmas Generated in Si by 1.06- and 0.53-μm Picosecond Laser Pulses
,”
Phys. Rev. B
,
35
, pp.
8166
8176
.10.1103/PhysRevB.35.8166
16.
Bechtel
,
J. H.
,
Smith
,
W. L.
, and
Bloembergen
,
N.
,
1977
, “
Two-Photon Photoemission From Metals Induced by Picosecond Laser Pulses
,”
Phys. Rev. B
,
15
, pp.
4557
4563
.10.1103/PhysRevB.15.4557
17.
Sebenne
,
C.
,
Bolmont
,
D.
,
Guichar
,
G.
, and
Balkanski.
M.
,
1975
, “
Surface States From Photoemission Threshold Measurements on a Clean, Cleaved, Si (111) Surface
,”
Phys. Rev. B
,
12
, pp.
3280
3285
.10.1103/PhysRevB.12.3280
18.
Eymard
,
R.
,
Gallouët
,
T. R.
, and
Herbin
,
R.
,
2000
, “
The Finite Volume Method
,”
Handbook of Numerical Analysis
,
P. G.
Ciarlet
and
J. L.
Lions
, eds.,
North-Holland, Amsterdam, The Netherlands
, Vol.
7
, pp.
713
1020
.
19.
Liu
,
X.
, and
Osher
,
S.
,
1998
, “
Convex ENO High Order Multi-Dimensional Schemes Without Field by Field Decomposition or Staggered Grids
,”
J. Comput. Phys.
,
142
, pp.
304
330
.10.1006/jcph.1998.5937
20.
Vidal
,
F.
,
Johnston
,
T. W.
,
Laville
,
S.
,
Barthélemy
,
O.
,
Chaker
,
M.
,
Le Drogoff
,
B.
,
Margot
,
J.
, and
Sabsabi
,
M.
,
2001
, “
Critical-Point Phase Separation in Laser Ablation of Conductors
,”
Phys. Rev. Lett.
,
86
, pp.
2573
2576
.10.1103/PhysRevLett.86.2573
21.
Perez
,
D.
, and
Lewis
,
L. J.
,
2003
, “
Molecular-Dynamics Study of Ablation of Solids Under Femtosecond Laser Pulses
,”
Phys. Rev. B
,
67
, p.
184102
.10.1103/PhysRevB.67.184102
22.
Lorazo
,
P.
,
Lewis
,
L. J.
, and
Meunier
,
M.
,
2006
, “
Thermodynamic Pathways to Melting, Ablation, and Solidification in Absorbing Solids Under Pulsed Laser Irradiation
,”
Phys. Rev. B
,
73
, p.
134108
.10.1103/PhysRevB.73.134108
23.
Hwang
,
D. J.
,
Grigoropoulos
,
C. P.
, and
Choi
,
T. Y.
,
2006
, “
Efficiency of Silicon Micromachining by Femtosecond Laser Pulses in Ambient Air
,”
J. Appl. Phys.
,
99
, p.
083101
.10.1063/1.2187196
24.
Besner
,
S.
,
Degorce
,
J. Y.
,
Kabashin
,
A. V.
, and
Meunier
M.
,
2005
, “
Influence of Ambient Medium on Femtosecond Laser Processing of Silicon
,”
Appl. Surf. Sci.
,
247
, pp.
163
168
.10.1016/j.apsusc.2005.01.137
25.
Hu
,
W.
,
Shin
,
Y. C.
, and
King
,
G. B.
,
2011
, “
Early-State Plasma Dynamics With Air Ionization During Ultrashort Laser Ablation of Metal
,”
Phys. Plasmas
,
18
, p.
093302
.10.1063/1.3633067
You do not currently have access to this content.