Pulsed laser photothermal displacement spectroscopy for surface studies

Karner, C.; Mandel, A. E.; Träger, F.

doi:10.1007/bf00618721

Cited by 56 publications

(11 citation statements)

References 10 publications

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“…As mentioned in ͑v͒ above, to the best of our knowledge, this simple technique has not been fully exploited previously. The feasibility of thermal diffusivity measurement by this method was reported by Karner et al 19 and by Vintsents and Sandomirskii. 20 However, no analyses of the data were performed to obtain actual thermal diffusivity values.…”

Section: Introductionmentioning

confidence: 77%

Thermal diffusivity measurement of solid materials by the pulsed photothermal displacement technique

Bennis

Vyas

Gupta

et al. 1998

Journal of Applied Physics

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Section: Introductionmentioning

confidence: 77%

Thermal diffusivity measurement of solid materials by the pulsed photothermal displacement technique

Bennis

Vyas

Gupta

et al. 1998

Journal of Applied Physics

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“…With the TPD technique, emphasis is placed on the study of thermomechanical processes in the time domain. This method has been applied previously as time-resolved damage monitor, material properties analyzer, ultra-sensitive and precise surface probe and noncontacting thermometer on materials [9,10] with reasonable successes. The main task of this work was divided into three components.…”

Section: Introductionmentioning

confidence: 93%

<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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“…Then the temperature rise is simply proportional to the optical energy per unit volume absorbed by the sample surface divided by the heat capacity. Equations (1) and (2) can be combined to yield the approximate J of duration tp needed to increase the surface temperature from an initial temperature T0 to a fmal temperature Tf for uniform irradiation of a semiinfinite sample by a rectangular pulse: PCATLH '0= (1-R)tp (3) where \T = Tf -To, and LH is interpreted as the generalized material heating depth. For an average fluence of Fave, the corresponding surface temperature rise T can be obtained from equation (3): (l-R)Fave T= (4) pCLH where Fave Iotp, and Fave is the average amount of energy incident per unit area with units J/cm2.…”

Section: Theory Of Laser Heating Of Semiconductorsmentioning

confidence: 99%

“…There have been numerous attempts by other investigators to observe precursor events leading to catastrophic dainage [1], but none so far have reported a practical solution to this difficult problem. This in-situ diagnostic method, the lTD technique, was first utilized by Olmstead et al [2] to measure optical absorption, and successfully demonstrated by Karner et al [3] for dye laser irradiation of metals. Since then it has been applied to measure the amount of laser energy deposited at an absorbing surface, to measure thin film thicknesses, and to analyze various physical properties and parameters with reasonable success.…”

Section: Introductionmentioning

confidence: 98%

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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Pulsed laser photothermal displacement spectroscopy for surface studies

Cited by 56 publications

References 10 publications

Thermal diffusivity measurement of solid materials by the pulsed photothermal displacement technique

Thermal diffusivity measurement of solid materials by the pulsed photothermal displacement technique

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

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

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