Recrystallization of Polycrystalline Silicon Over SiO 2 Through Strip Electron Beam Irradiation
- PDF / 1,842,750 Bytes
- 6 Pages / 417.6 x 639 pts Page_size
- 30 Downloads / 164 Views
RECRYSTALLIZATION OF POLYCRYSTALLINE SILICON OVER SiO2 THROUGH STRIP ELECTRON BEAM IRRADIATION
Y. HAYAFUJI, T. YANADA, H. HAYASHI*, K. E. WILLIAMS**, S. USUI, S. KAWADO, A. SHIBATA, N. WATANABE and M. KIKUCHI Sony Corporation Research Center, 174 Fujitsuka-cho, Hodogaya-ku, Yokohama, 240 Japan *Semiconductor Division, Sony Corporation, Asahi, Atsugi, 243 Japan **Energy Sciences, Inc., 8 Gill Street, Woburn, Mass., 01801 U.S.A.
ABSTRACT We have studied the influences of substrate orientation and growth direction on laterally seeded recrystallization of poly-crystalline silicon on a Si0 2 film through strip electron beam irradiation. We found that growth in a [110] direction produced films with better crystal quality than growth in a [100] direction on a (001) substrate, and that growth in a [211] direction provides better crystal quality than growth in a [011] direction on a (111) substrate. A simple model of the growth interface composed of f1111 planes is proposed. INTRODUCTION Much work has been carried out on the recrystallization of thin polyor amorphous silicon films on amorphous insulating materials (hereafter called SOIs) in order to develop 3-dimensional large-scale integrated silicon circuits in multiple active layer structure (called 3-D LSIs)[1-4]. Of the methods of regrowing a single crystalline silicon film on an insulating film, the laterally seeded recrystallization method using a laser or an electron beam is the most promising method for obtaining a large uniform SOI with high crystallographic quality[5,6]. We reported previously the successful laterally seeded recrystallization of SOI using a strip electron beam with a high energy density[7,8]. It was found that the SOI growth in the [110] direction gives films of better crystallographic quality than the growth in the [010] direction on (001) wafers(8]. In this paper, we present additional details on the effect of crystal growth direction on laterally seeded recrystallization and the resultant crystal structure under a high solidification front speed. EXPERIMENTAL The materials used in this study are described elsewhere[7,8]. In preparation for laterally seeded recrystallization, we made samples with two different structures, as is illustrated in Fig. 1. The samples in the first group, as shown in Fig. 1(a), (hereafter called mesa structure samples), had a seeding area on each side of an oxide island. A 0.5-pm-thick Si0 2 film 0 was thermally grown at 1000 C for 2 h in a wet 02 ambient. Seeding areas of 30 to 100 pm wide and Si0 2 islands also 30 to 100 pm wide and 2 cm long were formed by photolithography. Square Si0 2 islands with sides 100 pm were also formed. A 0.5-pm-thick poly-Si film was then deposited over the entire 0 surface of the wafers by chemical vapor deposition at 650 C using a mixture of SiH4 and N2 . The samples in the second group, as is shown in Fig. 1(b), (hereafter called LOCOS structure samples) had only one seeding area on one side of the underlying oxide film in an oxide crucible to achieve uni-directional stable recrysta
Data Loading...
