Electron-Beam Recrystallization of Silicon Layers on Silicon Dioxide
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ELECTRON-BEAM RECRYSTALLIZATION OF SILICON LAYERS ON SILICON DIOXIDE
Tomoyasu Inoue, Kenji Shibata, Koichi Kato, Toshio Yoshii, Iwao Higashinakagawa, Kenji Taniguchi, and Masahiro Kashiwagi Toshiba Research and Development Center, Toshiba Corp. 1 Komukai-Toshiba-cho, Saiwai-ku, Kawasaki 210, JAPAN
Abstract Recent progress of SOI growth by electron beam recrystallization is described. Transient temperature profile on the recrystallizing sample surface was analyzed experimentally by direct observation with a thermovision, which is essential for the understanding of crystal growth mechanism. SOI growth was performed by a spot beam annealing and a pseudo-line shaped beam annealing. The line shaped electron beam has been proved to be useful for large area crystallization. Emphasis was placed on lateral seeded recrystallization of silicon layer evaporated in an ultra high vacuum. Silicon layers with the seed area grown epitaxially during the evaporation and above 1 Fm thickness were successfully recrystallized, resulting in reproducible lateral epitaxy. The pseudo-line shaped electron beam formed by very high frequency oscillation enabled dimensional enlargement of lateral epitaxial growth. Crystalline properties were characterized by analyses of Rutherford backscattering and electron channeling pattern.
INTRODUCTION Silicon films on insulating materials (SOI) have been attracting an increasing attention because of its capability of higher electrical properties than that of SOS with poor interface characteristics and stacked structure for three dimensional devices. SOI growth has been investigated by many workers mainly using laser annealing or electron beam annealing. (1-11) The electron beam annealing has advantages over the laser annealing as follows (5); 1) high controllability in beam scanning, heating depth and beam shaping, 2) high output power, which leads to high throughput, and 3) beam power absorption independence of materials, electrical properties, optical properties and so on. A line electron beam has recently proved to be useful for growing large area SOI, because a large area can be melted in one scan of the beam. There are two methods in obtaining the line electron beam; one is line-shape beam as emitted from a cathod (9,10) , and the other is line-shaped beam formed by high frequency oscillation of a spot beam (11,12). The former is easy to obtain a high current beam with longer line length. The latter has high controllability of the beam intensity profile along the line direction and beam shape, such as crescent, "V" shape, "W" shape and so on. These line shaped beams seem to be effective in obtaining highly stabilized beam and controlling temperature profile at the growth front in SOI. It is necessary to understand the recrystallization process of thin silicon layers for realization of large area high quality SOI growth, which requires a knowledge of the transient temperature profile in the vicinity of the recrystallization front. Although computation results of the temperature profile have been re
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