Three-dimensional ordered nano-crystalline Si made by pulsed laser interference crystallization of a-Si:H/a-SiNx:H multilayers

We employed a KrF excimer pulsed laser source with wavelength of 248 nm, through a phase shifting mask grating to form a periodic, high intensity contrast patterned laser beam on the surface of a-Si:H (4 nm)/a-SiNx:H (10 nm) multilayers (MLs). The patterned local phase transition occurs in the each ultrathin a-Si:H sublayer and a nc-Si with stripe pattern structure is formed simultaneously. Micro-Raman measurements confirm crystallization in the stripe patterns. The cross-section transmission electron microscopy and atomic force microscopy images demonstrate that the crystallized sample shows a three-dimensional ordered structure of nc-Si, which has longitudinal order with 14 nm periodicity confined by SiNx sublayers in the MLs and lateral order with 2 mu m periodicity by patterned local crystallization. Finally, the laser induced constrained crystallization processes within a-Si:H/a-SiNx:H MLs both in the longitudinal and the lateral directions are discussed. (C) 2000 Published by Elsevier Science B.V. All rights reserved.