Ultralong Silicon Grains Grown by Excimer Laser Crystallization

Abstract

The factors affecting the elongation of Si grains were investigated for the excimer-laser-induced lateral grain growth method. The length of Si grains was found to depend on the laser light intensity profile, the waveform of the laser light pulse, particularly at its tail region, and the sample structure. Grains as long as 25 mm were successfully grown at room temperature using a combination of a V-shaped light intensity profile, a light pulse waveform with a long tail, and a stacked sample structure with a cap layer. Grains of 11 mm in length were also grown in a capless sample.

Infinite lateral growth of (001) single crystal strip in Ge film on SiO2 by micro-chevron laser scanning method

“…In pulsed laser annealing of Si films, adding a cap layer to the Si film increased heat capacity, prolonging the melting duration and promoting increased lateral growth. 26,27) Our findings support the notion that an extended melting duration is also critical for cw laser-induced lateral growth because insufficient melting may lead to spontaneous nucleation. This is significant for very thin Ge films or materials with comparatively small latent heat like Ge, emphasizing the need for a thick cap layer to augment heat capacity.…”

Ultrahigh-Performance Polycrystalline Silicon Thin-Film Transistors on Excimer-Laser-Processed Pseudo-Single-Crystal Films

“…Carriers are frequently scattered by the boundaries running across the channel, leading to their insufficient mobility and uniformity. Therefore, various advanced crystallization methods have been developed to grow long grains, [7][8][9][10][11][12] and grains much longer than the TFT feature size can now be grown.…”

High-performance poly-Si thin film transistors with highly biaxially oriented poly-Si thin films using double line beam continuous-wave laser lateral crystallization

“…For the higher current drivability of polycrystalline silicon (poly-Si) TFTs, novel techniques for further enhancement of the silicon grain size have been suggested. [1][2][3][4][5][6][7][8][9] Conventionally, in the fabrication of LTPS-TFTs, a-Si has been crystallized by pulsed laser irradiation called excimer laser annealing (ELA) and granular grains (³0.3 µm) have been formed. 10,11) The excimer laser irradiation time is almost 10-100 ns; thus, Si grains cannot grow larger and their size is nearly 300 nm.…”