Nonequilibrium behavior and defect diffusion in laser heating of semiconductors

Ho, Woei-Yun; Chun, Chi; Walser, R. M.; Becker, Michael F.

doi:10.1117/12.147420

Cited by 3 publications

(3 citation statements)

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“…For our experimental conditions, the melt threshold fluence is calculated to be 3.54 J/cm2 by choosing LH = 10 jnn in equation (4). This value agrees well with other numerical simulations of Si melting, namely, 3.15 J/cm2 from [10], 3.29 J/cm2 from [1 1], and 3.59 J/cm2 from computer modeling [12]. The most significant parameter in this equation is the value of LH.…”

Section: Theory Of Laser Heating Of Semiconductorssupporting

confidence: 87%

“…This numerical simulation was developed due to the growing interest in the effect oflaser-induced defect generation, transport, and accumulation [12]. The model generally involved solving the chemicalkinetic diffusion equations, defect generation and annihilation, coupled nonlinear differential equations of heat conduction and excess carrier generation and transport by a fmite difference technique.…”

Section: Computer Modelingmentioning

confidence: 99%

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Transient laser-induced surface deformation of silicon in relation to damage

Chun

Walser

et al. 1993

SPIE Proceedings

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Transient thermal expansion, heat generation and conduction, and nonlinear laser heating of single crystal Si wafers below and above the damage onset has been investigated via a laser pump-probe configuration. The Transient Photothermal Deflection (TPD) technique that we employed consisted of a 10 ns Nd YAG pump source at 1064 nm with 10 Hz repetition rate. A cw HeNe probe beam was used to probe the localized time dependent slope change ofilluniinated surface. The deflection of the reflected probe beam, centered at the maximum slope of the irradiated spot, was detected by a fast bicell photodiode. The deformation signals were recorded by a digital camera system in conjunction with a high-speed oscilloscope. The waveforms were later analyzed for surface angular deflection and vertical displacement based on the geometry of the Gaussian irradiation profile. Vertical displacement down to a few nm could be detected and converted into instantaneous peak surface temperature by a first-order, approximate thermal modeL Measured displacement and surface temperature were then compared to computer simulations at different fluence levels. They were found to be in excellent agreement to each other. In addition, single and multiple shot experiments were performed to obtained their respective damage onsets and thresholds. Measurement of peak surface deformation at subthreshold fluences gives insight into the thermomechanical processes which may play an important role in multi-pulse damage.

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Section: Theory Of Laser Heating Of Semiconductorssupporting

confidence: 87%

Section: Computer Modelingmentioning

confidence: 99%

Transient laser-induced surface deformation of silicon in relation to damage

Chun

Walser

et al. 1993

SPIE Proceedings

Self Cite

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show abstract

“…For our experimental conditions, the melt threshold fluence is calculated to be 3.54 J/cm2 by choosing LH = 10 jim in equation (1). This value agrees well with other numerical simulations of Si melting, namely, 3.15 J/cm2 from [16], 3.29 J/cm2 from [17], and 3.59 J/cm2 from computer modeling [18]. The most significant parameter in this equation is the value of LH.…”

Section: Simple Approximation For Laser Heating Of Bulk Semiconductorsmentioning

confidence: 52%

<title>Transient laser-induced surface deformation of Si-based multilayer structures</title>

Chun

Walser

et al. 1993

SPIE Proceedings

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Transient thermal expansion, heat generation and conduction, nonlinear laser heating and subsequent melting behaviors of polysificon/oxide/silicon wafer 'sandwich' structures have been investigated via a laser pump-probe technique. Laser pmcessing, damage, and characterization of bulk semiconductor materials has been extensively investigated. However, less is known about the mechanisms of laser-induced damage for multilayer structures such as CCD imaging arrays. In order to develop damage resistant sensors and better isolation for sensors used in laser environments, it is necessary to understand the processes contributing to the laser hardness and damage of these sensors. We designed experiments to measure the transient thermomechanical and laser-damage characteristics of multilayer systems that resemble CCD devices. The final objective was to gain some insight into the dominant mechanisms responsible for laser-induced degradation in CCD imaging arrays and devices of similar structures. Positive identification of a precursor event signaling the onset of catastrophic damage and identification of the weakest link elements on the sensor array will be essential for making design or processing modifications to improve hardness. It is our goal in this paper to contribute to the above objectives by describing investigations of laser-induced damage to silicon-based multilayer structures. We performed single and multiple shot experiments to obtain morphological damage thresholds for a sample set of various isolation oxide and polysilicon layer thickness. The transient photothermal deflection (TPD) technique that we employed consisted of a 10 ns pulsed Nd: YAG pump laser source at 1064 nm wavelength with a 10 Hz repetition rate. A cw HeNe laser was to probe the localized, timedependent slope change of the illuminated surface. The deflection of the reflected probe beam was detected by a fast bicell photodiode with temporal resolution of 20 ns. The deformation signals were recorded by a digital camera system and highspeed oscilloscope. The waveforms were later analyzed to extract the peak angular deflection and the vertical displacement based on the geometry of the Gaussian irradiation profile. Vertical displacement down to a few nm could be detected. Measured displacement and surface temperature were then compared to computer simulations at different fluence levels for bulk silicon. They were found to be in excellent agreement to each other. In addition, single shot experiments were performed to obtain their respective damage onsets for various Si-based multilayer samples. Results indicated that the top polysilicon layer received the major portion of the photon energy deposited before substantial heat was conducted into the Si substrate. And it had a lower melt onset than bulk silicon due to strong nonlinear absorption. Laser-induced damage to polysilicon layer was also related to film microstructures and degree of thermal isolation which depended on the oxide thickness. Measurement of peak surface deformation at subthresho...

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Laser-induced damage threshold of silicon in millisecond, nanosecond, and picosecond regimes

Wang

Shen

Lü

et al. 2010

Journal of Applied Physics

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Millisecond, nanosecond, and picosecond laser pulse induced damage thresholds on single-crystal are investigated in this study. The thresholds of laser-induced damage on silicon are calculated theoretically for three pulse widths based on the thermal damage model. An axisymmetric mathematical model is established for the transient temperature field of the silicon. Experiments are performed to test the damage thresholds of silicon at various pulse widths. The results indicate that the damage thresholds obviously increase with the increasing of laser pulse width. Additionally, the experimental results agree well with theoretical calculations and numerical simulation results.

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Nonequilibrium behavior and defect diffusion in laser heating of semiconductors

Cited by 3 publications

References 0 publications

Transient laser-induced surface deformation of silicon in relation to damage

Transient laser-induced surface deformation of silicon in relation to damage

<title>Transient laser-induced surface deformation of Si-based multilayer structures</title>

Laser-induced damage threshold of silicon in millisecond, nanosecond, and picosecond regimes

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