Unseeded Crystal Growth of (100)-Oriented Grain-Boundary-Free Si Thin-Film by a Single Scan of the CW-Laser Lateral Crystallization of a-Si on Insulator

Abstract

Laser crystallization of a-Si film on insulating substrate is a promising technology to fabricate three-dimensional integrations (3D ICs), flat panel displays (FPDs), or flexible electronics, because the crystallization can be performed on room temperature substrate to avoid damage to the underlying devices or supporting plane. Orientation-controlled grain-boundary-free films are required to improve the uniformity in electrical characteristics of field-effect-transistors (FETs)fabricated in those films. This paper describes the recently found simple method to obtain {100}-oriented grain-boundary-free Si thin-films stably, by using a single scan of continuous-wave (CW)-laser lateral crystallization of a-Si with a highly top-flat line beam with 532 nm wavelength at room temperature in air. It was difficult to control crystal orientations in the grain-boundary-free film crystallized by the artificial modulation of solid-liquid interface, and any other trial to obtain preferential surface orientation with multiple irradiations resulted in grain boundaries. The self-organized growth of the {100}-oriented grain-boundary-free films were realized by satisfying the following conditions: (1) highly uniform top-flat line beam, (2) SiO2 cap, (3) low laser power density in the vicinity of the lateral growth threshold, and (4) single scan crystallization. Higher scan velocity makes the process window wide for the {100}-oriented grain-boundary-free film. This crystallization is very simple, because it is performed by a single unseeded scan with a line beam at room temperature substrate in air.

Laser Thermal Processing of Group IV Semiconductors for Integrated Photonic Systems

“…[ 118 ] Moreover, it has recently been demonstrated that a silica cap is necessary to be able to obtain grain‐boundary‐free lateral crystallization of a‐Si thin films on glass substrates, using a fast CW laser scan. [ 119 ] Therefore, laser thermal processing of patterned and glass‐encapsulated Si waveguides could result in low optical losses similar to those achieved in SOI platforms and in the Si core glass‐clad fibers, but with the prospect of allowing for photonic integration within multilayered systems built on cheaper, bulk Si platforms.…”

Post treatment of plasma enhanced atomic layer deposited MoS2 via ultra short pulse laser to increase the crystallinity

“…Laser processing of materials is suitable to modify the crystal structure to achieve a higher degree of crystallinity. Amorphous silicon films and optical fibers were crystallized by long-pulsed 10 or continuous wave 11,12 laser. Adopting this method to MoS 2 , the crystallinity of amorphous magnetron sputtered MoS 2 films on polymer was increased.…”

Ultrashort‐Pulsed‐Laser Annealing of Amorphous Atomic‐Layer‐Deposited MoS2 Films

“…Laser processing of materials can modify the crystal structure to achieve a higher degree of crystallinity. Amorphous silicon films and optical fibers were crystallized by long-pulsed [13] or continuous wave (cw) [14,15] laser. Adopting this method to MoS 2 , the crystallinity of amorphous magnetron sputtered MoS 2 films on polymer was increased.…”