Influence of laser wavelength and pulse duration on processing of crystalline silicon

2008 ◽  
Author(s):  
Oliver Haupt ◽  
Aart Schoonderbeek ◽  
Lars Richter ◽  
Rainer Kling ◽  
Andreas Ostendorf
Keyword(s):  
Pulse Duration ◽  
Crystalline Silicon ◽  
Laser Wavelength

scholarly journals Effects of Pulse Duration and Heat on Laser-Induced Periodic Surface Structures

2020 ◽  
Vol 14 (4) ◽  
pp. 552-559
Author(s):  
Shuhei Kodama ◽  
Keita Shimada ◽  
Masayoshi Mizutani ◽  
Tsunemoto Kuriyagawa ◽  
◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Pulse Duration ◽  
Pulse Laser ◽  
Pulsed Laser ◽  
Laser Wavelength ◽  
Surface Structures ◽  
Pulsed Lasers ◽  
Efficient Technology ◽  
Periodic Surface ◽  
Ultrashort Pulsed Lasers

Compared with traditional nanotexturing methods, an ultrashort-pulsed laser is an efficient technology of fabricating nanostructures called laser-induced periodic surface structures (LIPSS) on material surfaces. LIPSS are easily fabricated when the pulse duration is shorter than collisional relaxation time (CRT). Accordingly, ultrashort-pulsed lasers have been mainly used to study LIPSS, but they unstably irradiate while requiring high costs. Although long-pulsed lasers have low cost and high stability, the phenomena (such as the effect of pulse duration, laser wavelength, and heat) of the LIPSS fabricated using short-pulsed lasers with the pulse duration close to the maximum CRT, which is greater than femtosecond, have not been clarified. However, the nanosecond pulse laser has been reported to produce LIPSS, but those were unclear and ununiform. In this study, the short-pulsed laser with the pulse duration of 20 ps, which is close to the maximum CRT, was employed to clarify the effects of pulse duration and heat on the fabrication of LIPSS and to solve problems associated with ultrashort-pulsed lasers. First, a finite-difference time-domain simulation was developed at 20-ps pulse duration to investigate the effects of irradiation conditions on the electric-field-intensity distribution. Subsequently, experiments were conducted using the 20-ps pulse laser by varying conditions. The aspect ratio of the LIPSS obtained was greater than that of the LIPSS fabricated using ultrashort-pulsed lasers, but LIPSS were not fabricated at 355- and 266-nm laser wavelength. In addition, the short-pulsed laser experienced thermal influences and a cooling material was effective for the fabrication of LIPSS with high-aspect-ratio. This demonstrates the effects of pulse duration close to the CRT and heat on the fabrication of LIPSS.

scholarly journals Micro/Nano Amorphization/Oxidation Of Silicon Induced By High Repetition Femtosecond Laser Pulses

2021 ◽  
Author(s):  
Amirkianoosh Kiani
Keyword(s):  
Solar Cell ◽  
Femtosecond Laser ◽  
Surface Temperature ◽  
Pulse Duration ◽  
Analytical Model ◽  
Repetition Rate ◽  
Crystalline Silicon ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Laser Parameters

The main aim of this thesis is to develop a new method for direct micro/nano amorphization/oxidation of silicon using femtosecond laser irradiation and its applications in maskless lithography and solar cell fabrication. Amorphization and oxidation occur when crystalline silicon is exposed to the irradiation of femtosecond laser pulses below the ablation threshold. Mechanisms of morphization and oxidation were discussed and the surface temperature model was developed to study the relation between laser parameters and observed amorphization and oxidation. A systematic theoretical and experimental study of the influence of the laser parameters on the quality of amorphorized area and the size of the feature fabricated through amorphization has been studied. It was found that during the process of silicon amorphization and oxidation, the higher repetition rate of laser pulses yields smooth morphology with better repeatability. Increasing pulse duration and number of pulses were seen to increase the line width. However, increasing the number of pulses does not result in ablation of the target area. An analytical model was developed for the calculation of the average surface temperature after n-pulses. The effect of the laser pulse width was investigated by developing an analytical model for the calculation of the non-dimensional surface temperature with various pulse widths. It was found from experimental and analytical results that for a constant power and repetition rate, an increase in the pulse duration corresponds to a significant increase in the surface temperature. It results in an increase in the amount of modified material as well as improvement of light absorption in the case of amorphization. The main aim of this thesis is to develop a new method for direct micro/nano amorphization/oxidation of silicon using femtosecond laser irradiation and its applications in maskless lithography and solar cell fabrication.Amorphization and oxidation occur when crystalline silicon is exposed to the irradiation of femtosecond laser pulses below the ablation threshold. Mechanisms of morphization and oxidation were discussed and the surface temperature model was developed to study the relation between laser parameters and observed amorphization and oxidation. A systematic theoretical and experimental study of the influence of the laser parameters on the quality of amorphorized area and the size of the feature fabricated through amorphization has been studied. It was found that during the process of silicon amorphization and oxidation, the higher repetition rate of laser pulses yields smooth morphology with better repeatability. Increasing pulse duration and number of pulses were seen to increase the line width. However, increasing the number of pulses does not result in ablation of the target area. An analytical model was developed for the calculation of the average surface temperature after n-pulses.The effect of the laser pulse width was investigated by developing an analytical model for the calculation of the non-dimensional surface temperature with various pulse widths. It was found from experimental and analytical results that for a constant power and repetition rate, an increase in the pulse duration corresponds to a significant increase in the surface temperature. It results in an increase in the amount of modified material as well as improvement of light absorption in the case of amorphization.The amorphous silicon and silicon oxide can act as an etch stop. Therefore, maskless lithography iis possible with the direct patterning (amorphization and oxidation) of crystalline silicon. Experimental results have proved the feasibility of the proposed concepts. The thin-film of amorphous silicon generated on the silicon substrate has a potential for use in photovoltaic devices and solar cell fabrication. In comparison with previous methods, the direct oxidation/amorphization of silicon induced by the femtosecond laser is a maskless single-step technique which offers a higher flexibility and reduced processing time.

Heterogeneous Nucleation of Spatially Coherent Damage Structures in Crystalline Silicon with Picosedcond 1.06 μm and 0.53 μm Laser Pulses

1980 ◽  
Vol 1 ◽  
Author(s):  
R.M. Walser ◽  
M.F. Becker ◽  
J.G. Ambrose ◽  
D.Y. Sheng
Keyword(s):  
Electric Field ◽  
Heterogeneous Nucleation ◽  
Crystallographic Orientation ◽  
Free Space ◽  
Crystalline Silicon ◽  
Laser Pulses ◽  
Laser Wavelength ◽  
Beam Spot ◽  
Polarized Beams ◽  
Linearly Polarized

Several types of periodic ripple structures have been observed on the surface of solids that have been laser irradiated with beam intensities near their melting thresholds.1-7 We restrict our attention here to the coherent, onedimensional (RD) gratings induced by linearly polarized beams.3-7 These gratings have a period close to the free space laser wavelength (λ0) for normally incident beams and are normally found in the beam spot near the melt boundary (Fig. 1). The grating lines are always perpendicular to the optical electric field Ei independent of the crystallographic orientation of the sample.

Effect of Laser Wavelength and Pulse Duration on Laser-Light Absorption and Back Reflection

1982 ◽  
Vol 48 (15) ◽  
pp. 1018-1021 ◽  
Author(s):  
C. Garban-Labaune ◽  
E. Fabre ◽  
C. E. Max ◽  
R. Fabbro ◽  
F. Amiranoff ◽  
...  
Keyword(s):  
Pulse Duration ◽  
Light Absorption ◽  
Laser Light ◽  
Laser Wavelength ◽  
Back Reflection

scholarly journals Micro/Nano Amorphization/Oxidation Of Silicon Induced By High Repetition Femtosecond Laser Pulses

2021 ◽  
Author(s):  
Amirkianoosh Kiani
Keyword(s):  
Solar Cell ◽  
Femtosecond Laser ◽  
Surface Temperature ◽  
Pulse Duration ◽  
Analytical Model ◽  
Repetition Rate ◽  
Crystalline Silicon ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Laser Parameters

The main aim of this thesis is to develop a new method for direct micro/nano amorphization/oxidation of silicon using femtosecond laser irradiation and its applications in maskless lithography and solar cell fabrication. Amorphization and oxidation occur when crystalline silicon is exposed to the irradiation of femtosecond laser pulses below the ablation threshold. Mechanisms of morphization and oxidation were discussed and the surface temperature model was developed to study the relation between laser parameters and observed amorphization and oxidation. A systematic theoretical and experimental study of the influence of the laser parameters on the quality of amorphorized area and the size of the feature fabricated through amorphization has been studied. It was found that during the process of silicon amorphization and oxidation, the higher repetition rate of laser pulses yields smooth morphology with better repeatability. Increasing pulse duration and number of pulses were seen to increase the line width. However, increasing the number of pulses does not result in ablation of the target area. An analytical model was developed for the calculation of the average surface temperature after n-pulses. The effect of the laser pulse width was investigated by developing an analytical model for the calculation of the non-dimensional surface temperature with various pulse widths. It was found from experimental and analytical results that for a constant power and repetition rate, an increase in the pulse duration corresponds to a significant increase in the surface temperature. It results in an increase in the amount of modified material as well as improvement of light absorption in the case of amorphization. The main aim of this thesis is to develop a new method for direct micro/nano amorphization/oxidation of silicon using femtosecond laser irradiation and its applications in maskless lithography and solar cell fabrication.Amorphization and oxidation occur when crystalline silicon is exposed to the irradiation of femtosecond laser pulses below the ablation threshold. Mechanisms of morphization and oxidation were discussed and the surface temperature model was developed to study the relation between laser parameters and observed amorphization and oxidation. A systematic theoretical and experimental study of the influence of the laser parameters on the quality of amorphorized area and the size of the feature fabricated through amorphization has been studied. It was found that during the process of silicon amorphization and oxidation, the higher repetition rate of laser pulses yields smooth morphology with better repeatability. Increasing pulse duration and number of pulses were seen to increase the line width. However, increasing the number of pulses does not result in ablation of the target area. An analytical model was developed for the calculation of the average surface temperature after n-pulses.The effect of the laser pulse width was investigated by developing an analytical model for the calculation of the non-dimensional surface temperature with various pulse widths. It was found from experimental and analytical results that for a constant power and repetition rate, an increase in the pulse duration corresponds to a significant increase in the surface temperature. It results in an increase in the amount of modified material as well as improvement of light absorption in the case of amorphization.The amorphous silicon and silicon oxide can act as an etch stop. Therefore, maskless lithography iis possible with the direct patterning (amorphization and oxidation) of crystalline silicon. Experimental results have proved the feasibility of the proposed concepts. The thin-film of amorphous silicon generated on the silicon substrate has a potential for use in photovoltaic devices and solar cell fabrication. In comparison with previous methods, the direct oxidation/amorphization of silicon induced by the femtosecond laser is a maskless single-step technique which offers a higher flexibility and reduced processing time.

Time Resolved Transmission and Reflectivity of Pulsed Ruby Laser Irradiated Silicon

1981 ◽  
Vol 4 ◽  
Author(s):  
Douglas H. Lowndes ◽  
G. E. Jellison ◽  
R. F. Wood
Keyword(s):  
Ruby Laser ◽  
Crystalline Silicon ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Quantitative Agreement ◽  
Laser Wavelength ◽  
Time Resolved ◽  
Model Calculations ◽  
Thermal Melting ◽  
Apparent Disagreement

ABSTRACTThe time resolved optical transmission, T (atλ = 1152 nm), and reflectivity, R (at 633 nm and 1152 nm), have been measured for n-type single crystalline silicon (c-Si) during and immediately after pulsed ruby laser irradiation (λ = 693 nm, FWHM pulse duration 14 nsec), for a range of pulsed laser energy densities, El. The T is found to go to zero, and to remain at zero, for a period of time that increases with increasing El, in apparent disagreement with earlier measurements elsewhere that used semi-insulating Si and a different pulsed laser wavelength. Measured reflectivities during the high R phase agree within experimental error with reflectivities calculated from the optical constants of molten Si. Quantitative agreement is also found between both our T and R measurements and detailed time– and El-dependent results of thermal melting model calculations.

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