A kinetic simulation study of the mechanisms of aluminum induced layer exchange process

Abstract

The aluminum induced layer exchange (ALILE) process allows the formation of thin polycrystalline Si (poly-Si) layers of large grain size on foreign substrates such as glass at low process temperatures. This paper is devoted to a computer simulation study of the kinetics of the ALILE process taking into account the mechanisms of its separate stages: Si diffusion in the AlOx membrane, nucleation and growth of grains, and the formation of preferential (100) orientation. The characteristics of the ALILE process are explained based on the evolution of the Si concentration within the Al layer. In particular it is demonstrated that the characteristic suppression of nucleation after short annealing times results from a decrease in the Si concentration in the Al layer due to the growth of existing grains. A number of important parameters of ALILE process are estimated comparing the results of simulation to the experimental data.

Growth promotion of Al-induced crystallized Ge films on insulators by insertion of a Ge membrane below the Al layer

“…Ge nucleation occurs as a result of supersaturation of the Al with Ge [15,18]. Hence, a 131 thicker ti provides greater concentration of Ge in the Al, which results in faster 132 nucleation because of faster supersaturation of the Al with Ge, as shown in Fig.…”

“…3(c) [15][16][17][18][19][20][21][22]25]. In contrast to the nucleation rate, the lateral growth 137 rate decreased with increasing ti, as shown in Fig.…”

Highly (111)-oriented Ge thin films on insulators formed by Al-induced crystallization

“…13,14 This trend can be explained as follows: The low T a decreases the reaction rates by the Arrhenius law 20 ; and the longer t air thickens the AlO x intermediate layer thickness, and thereby reducing the interdiffusion rate of Al and Ge atoms. 12,13 These orientation mappings clearly indicate that the orientation of the AIC-Ge depends on both T a and t air : (111) orientation becomes dominant with decreasing T a and increasing t air . This behavior is also the same as the AIC-Si.…”

“…[10][11][12][13][14][15] This AIC technique enables us to form large-grain (diameters: 10-100 lm) polycrystalline Si films at relativity low temperatures (420-550 C) through the exchange between the Al and Si layers during annealing. [10][11][12][13][14][15] Moreover, we controlled the orientations of the Al-induced-crystallized Si (AIC-Si) films to either (100) or (111) plane by modulating the annealing temperatures, the thickness of Al and Si layers, and the thickness of Al native oxide (AlO x ) interlayers between Si and Al layers. [13][14][15] CVD of Si layers onto the AIC-Si thin-film is a promising approach to fabricate the low-defect Si layers on glass substrates.…”

The Larger Grain and (111)-Orientation Planes of Poly-Ge Thin Film Grown on SiO<sub>2</sub> Substrate by Al-Induced Crystallization

“…Al induced crystallization of a-Si thin films had also the same tendency. [9] This tendency can be illustrated as follows: The lower T a reduces the reaction rate of Al and Ge atoms by the Arrhenius law [10]; and the longer t air thickens the AlO x diffusion controlinterlayer, and decreases the diffusion rate of Al and Ge atoms [11]. The (111)-orientation planes of a-Ge thin film also depend on both T a and t air during Al induced crystallization, and the (111)-orientation planesbecome dominant with decreasing T a and increasing t air .…”