The epitaxial lateral overgrowth of silicon by two-step liquid phase epitaxy

This paper reports on the results of the epitaxial lateral overgrowth of silicon on silicon substrates patterned with SiO2 masks, carried out in two-step growth mode. The new approach to the process of liquid phase epitaxy growth is based on the fact that the saturation and growth occur in the separate steps under Ar atmosphere, i.e., the sample substrate is introduced into the tube after the saturation step and cooling the apparatus to the room temperature. What is next, the temperature is raised to the initial growth temperature, and after a short time (about 5 min) the solution and substrate come into contact, and the growth begins. Undoubtedly, the short time that the sample substrate spends in the hot gaseous Ar atmosphere is an advantage of the two-step experiment, as the probability of the impurity deposition on the substrate decreases in comparison to the one-step experiment. The results of the experiments carried out in two-step mode show that it is possible to optimize the experimental conditions of the process of growth to obtain epilayers of the highest aspect ratio and the lowest defect density at the same time, which in the cases studied means that the growth is performed with 0.5 degrees C/min cooling rate at constant supercooling equal Delta T = 60 degrees C. What is more, it has been shown, that the multiple use of the same growth solution is possible, on condition that the supersaturation of the solution will be maintained by lowering the initial growth temperature during the latter use in comparison with the former use of the same solution. In the result of that the layers of slightly different values of the their dimensions are obtained. (c) 2006 Elsevier B.V. All rights reserved.