Effect of CW Laser Annealing on Silicon Surface for Application of Power Device

As application of re-activation of backside on power device Insulated Gate Bipolar Transistor (IGBT), laser annealing was employed to irradiate amorphous silicon substrate, and resistivities were measured using four point probe measurement. For annealing the amorphous silicon two lasers were used at wavelength of visible green (532 nm) together with Infrared (793 nm). While the green laser efficiently increased temperature at top surface the Infrared laser reached more deep inside and was effective for melting the top surface. A finite element method was employed to evaluate time dependent thermal distribution in silicon substrate.

Authors:

• Satoru Kaneko
• Takeshi Ito
• Kensuke Akiyama
• Manabu Yasui
• Chihiro Kato
• Satomi Tanaka
• Yasuo Hirabayashi
• Takeshi Ozawa
• Akira Matsuno
• Takashi Nire
• Hiroshi Funakubo
• Mamoru Yoshimoto

Keywords:

• laser
• annealing
• silicon
• recrystallization
• thermal distribution
• resistivity
• finite element method
• absorption
• melting point
• latent heat of fusion.

References:

[1] J. P. Biersack and L. Haggmark, "Srim - the stopping and range of ions
in matter," Nucl. Instr. and Meth., vol. 174, p. 257, 1980.
[2] J. F. Ziegler, J. P. Biersack, and M. D. Ziegler, SRIM: The Stopping and
Range of Ions in Matter. 860 Aviation Parkway; Suite 300; Morrisville,
NC, 27560 USA: Lulu Press Co., 2008.
[3] S. de Unamuno and E. Fogarassy, "A thermal description of the melting
of c- and a-silicon under pulsed excimer lasers," Appl. Surf. Sci., vol. 36,
pp. 1 - 11, 1989.
[4] R. F. Wood and G. E. Giles, "Macroscopic theory of pulsed-laser
annealing. i. thermal transport and melting," Phys. Rev. B, vol. 23, no. 6,
p. 2923, 1981.
[5] K. Shimizu, S. Imai, O. Sugihara, and M. Matsumura, "Transient temperature
profiles in silicon films during pulsed laser annealing," Jpn. J.
Appl. Phys., vol. 30, no. 11A, pp. 2664-2672, 1991.
[6] J. R. Kohler, R. Dassow, and J. Werner, "Numerical modeling of high
repetition rate pulsed laser crystallization of silicon films on glass," Mat.
Res. Soc. Sympo. Proc., vol. 685E, pp. D10.3.1-D10.3.6, 2001.