Nucleation and growth kinetics during metal-induced layer exchange crystallization of Ge thin films at low temperatures

Abstract

Interface-controlled layer exchange in metal-induced crystallization of germanium thin films Appl. Phys. Lett. 97, 082104 (2010); 10.1063/1.3480600Crystallization kinetics of ultrathin amorphous Si film induced by Al metal layer under thermal annealing and pulsed laser irradiation

- Introduction to Metal-Induced Crystallization

“…As a result, the a-Ge phase is very fast fully crystallized, long before a complete layer exchange, as induced by crystallization at the original Al GBs, has been realized, which agrees with the experimental observations [7,11,12,57]. Furthermore, in a recent study [16,58], by creating an interfacial Ge oxide layer between the c-Al and a-Ge sublayers, the interface-mediated nucleation of c-Ge in c-Al/a-Ge bilayers can be suppressed due to the modified interface energetics by the presence of the interfacial oxide layer. Then the Al GBs exclusively mediate the low-temperature crystallization of a-Ge, and layer exchange of Al and Ge sublayers upon Al-induced crystallization of a-Ge was observed indeed (similar to that observed in the c-Al/a-Si bilayers) [58].…”

“…Amorphous semiconductors such as silicon and germanium can crystallize at a temperature much lower than their "bulk" crystallization temperatures when they are put in direct contact with a metal, such as Al [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17], Au [18][19][20][21][22], Ag [23][24][25], Ni [26][27][28][29][30][31][32][33], Cu [34][35][36], and Pd [37,38]. This phenomenon, which was firstly observed more than 40 years ago for amorphous germanium [39], is now commonly referred to as metal-induced crystallization (MIC) [40][41][42][43].…”

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

“…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 . This action is also the same as the a-Si thin film during Al induced crystallization [12]. The reason for this behavior can be explained as follows: The Ge nuclei happen on the surface of SiO 2 substrate because the thickness of Ge and Al thin films is 50 nm [13], respectively, and (111)-orientation planes have the lowest interfacial energy in the diamond structure [14].…”

An assessment on crystallization phenomena of Si in Al/a-Si thin films via thermal annealing and ion irradiation

“…Al is successful in bringing out the crystallization at very low temperature, as it is a post-transition metal, which constitutes a simple eutectic binary system with Si, and is not involved in the formation of any compound phases via AIC. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] The AIC process in various Al/a-Si systems has been extensively investigated in the last decade because of applications of poly-Si in low-temperature production of high-performance solar cells, at-panel displays, and high-density data storage devices. Many groups investigated the impact of different parameters such as Al and Si layer thicknesses, layer orders, layer interface types, and Al to Si content ratios on the AIC process.…”

“…[12][13][14][15][16][17][18][19][20][21][22] These studies were aimed at lowering the crystallization temperature, shortening the annealing time required for the crystallization of a-Si layer, and for obtaining poly-Si thin lms. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] Nast et al 9,27 studied the effect of Al layer thickness on the morphology of crystalline-silicon (c-Si). In their study, the AIC samples having a-Si layer one-half of the thickness of the Al layer were found to produce a porous structure and therefore, no continuous lm was observed.…”