Non-ablative texturing of silicon surface with a continuous wave fiber laser

Abstract

Laser surface texturing based on ablation has been widely used, but hardly any reports can be found on non-ablative laser surface texturing. Silicon is highly transparent to the infrared wavelength of fiber laser (λ = 1090 nm) and thus regarded as an unsuitable tool for the purpose of surface texturing. However, we succeeded in using a continuous wave fiber laser to produce regular arrays of sub-micron bumps on silicon surface. The approach is shown to be based on laser-induced oxidation of silicon.

Numerical Simulation of Non-Ablative Laser Texturing of Silicon Surface with a Continuous Wave Fiber Laser

“…If localized thermal oxidation of Si accounts for formation of the regular bumps as suggested earlier, 16 It is found in many studies 29-37 that thermal oxidation of Si surface generally occurs in the temperature range 1000-1600 K and that 56% of the oxide thickness rises above the original silicon surface. For the laser power of 11.5 W used, the peak temperature is around 600 K (Fig.…”

“…Recently, we developed a novel technique to pattern Si surface by non-ablative laser texturing using continuous wave fiber laser ( = 1090 nm). 15 16 As Si is known to be highly transparent to the infrared wavelength, the fiber laser is not regarded as a suitable tool for texturing of Si surface. We explained the non-ablative surface texturing in terms of laser-induced localized thermal oxidation.…”

“…We explained the non-ablative surface texturing in terms of laser-induced localized thermal oxidation. 15 16 However, the proposed mechanism is based upon qualitative analyses only. The current study aimed to gain better understanding of the non-ablative texturing mechanism through numerical simulation.…”

Other Methods of Polymer Surface Modifications

“…Another approach to texturing Si surface is by laser-induced surface oxidation (Farrokhi et al, 2012(Farrokhi et al, , 2014. This nonablative laser texturing method was successfully achieved using a continuous wave fiber laser to produce regular arrays of submicron bumps on a silicon surface, as shown in Figure 10.17.…”

A study on co-axial water-jet assisted fiber laser grooving of silicon

“…The variation in laser parameter led to different geometrical dimensions of the structures after anisotropic etching. A continuous wave (CW) fiber laser ( = 1090 nm) in modulated mode was successfully utilized to produce non-ablative textures by Farrokhi et al (2012). They produced textured bumps generated due to the oxidation of (Cherneka and Orson, 2002), (b) Temperature dependent thermo-physical properties of silicon, conductivity (Pronko et al, 1995), density (Ohsaka et al, 1997), specific heat (Cp) (Grigoropoulos et al, 1986). silicon during laser irradiation in ambient air.…”