Laser interference structuring of a-Ge films on GaAs

Abstract

We have investigated the laser interference crystallization ͑LIC͒ of amorphous germanium films on ͑100͒-oriented GaAs substrates using nanosecond laser pulses. We demonstrate that LIC can produce periodic arrays of epitaxially crystallized Ge lines on GaAs with submicrometer widths. The gratings display a surface undulation with faceted surfaces, which depends on laser fluency. The undulation is attributed to the lateral solidification process induced by the temperature gradients created during the LIC process.

Analysis of the relief of the GaAs surface formed upon exposure to diffraction-modulated laser radiation

“…Among the well-known methods of forming surface semiconductor structures with application of laser technologies are repeated pulsed irradiation of a local surface region, laser scanning with a fixed number of irradiation pulses [1], and pulsed-periodic irradiation with the interference distribution of the beam intensity [2,3]. In the present work, the GaAs surface was irradiated by a single pulse through diffraction masks having different shapes.…”

Periodic subsurface structures in GaAs formed by spatially modulated nanosecond pulse laser irradiation

“…Laser technologies of creation of semiconductor structures allow one to set the required energy distribution on irradiated surfaces. It was succeeded to form nanostructures with specific properties on the GaAs surface by different methods of laser radiation intensity modulation [1][2][3][4][5]. For a modification of the thin subsurface layer of a semiconductor, it is necessary to use the fundamental absorption of short laser radiation pulses with a certain energy distribution on the irradiated surface [5,6].…”