Nanosecond laser-induced thermal evaporation of silicon carbide

• Published in: International journal of thermophysics 1996-09, Vol.17 (5), p.1079-1087
• Main Authors: REITANO, R, BAERI, P
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Electron and ion emission by liquids and solids; impact phenomena; Equations of state, phase equilibria, and phase transitions; Evaporation; Exact sciences and technology; Excimer lasers; Impact phenomena (including electron spectra and sputtering); Laser beam effects; Laser pulses; Laser-beam impact phenomena; Melting; Physics; Pressure; Single crystals; Specific phase transitions; Surface treatment; Temperature; Thermal effects; Vacuum
• ISSN: 0195-928X; 1572-9567
• DOI: 10.1007/BF01441996

Excimer (XeCl) laser pulses, 15 ns in duration and with fluences up to 10 J multiplied by cm super(-2), have been employed to induce melting and evaporation of 6H-SiC thin layers in vacuum. Sample surface modification in the nanosecond time scale have been monitorized in situ by optical probing. Eventually, the ablation product was collected on silicon single-crystal substrates placed in front of the SiC target. Modeling of the heating and the thermal evaporation processes resulted in estimation of surface temperatures as high as 10,000 K, evaporation rates of the order of 10 super(25) molecules multiplied by cm super(-2) multiplied by s super(-1) and recoil pressures of the order of 1 GPa. Comparison with experiments showed that the simple mechanism of purely thermal evaporation is able to describe the process of particle removal from a surface by short laser pulses only in the low-energy density range. Above a certain threshold the model breaks down and other mechanisms have to be considered.