Title :
Defect density of crystalline Si films fabricated by high-speed zone melting crystallization for solar cells
Author :
Yokoyama, Shuhei ; Ihara, Manabu ; Hashizume, Hiroaki ; Yokoyama, Chiaki ; Komiyama, Hiroshi
Author_Institution :
Inst. of Multidisciplinary Res. for Adv. Mater., Tohoku Univ., Sendai, Japan
Abstract :
The defect density of crystalline Si films fabricated by high-speed zone melting crystallization (ZMC) of amorphous Si (a-Si) and by high-speed zone melting re-crystallization (ZMR) of polycrystalline Si (poly-Si) was investigated by using electron spin resonance (ESR). The crystal defect density of the sandwich-structured a-Si ZMC films (SiO2 film/Si film/SiO2 film) was lower than that of the sandwich-structured poly-Si ZMR films for a lower-heater temperature range of 1470°C to 1570°C and for an upper-heater scan-speed range of 0.7-4.5 mm/s. The defect density of the bulk a-Si ZMC films was below the detection limit of ESR, even at high scan speed of 7.0 mm/s. Therefore, a-Si ZMC films can be used to fabricate solar cells that have an efficiency higher than those fabricated by current processes involving poly-Si ZMR films.
Keywords :
elemental semiconductors; paramagnetic resonance; semiconductor materials; semiconductor thin films; silicon; solar cells; zone melting recrystallisation; 1470 to 1570 degC; ESR; SiO2-Si-SiO2; ZMC; ZMR; amorphous Si; crystal defect density; crystalline Si films; defect density; efficiency; electron spin resonance; high-speed zone melting crystallization; high-speed zone melting re-crystallization; poly-Si; solar cells; Amorphous materials; Atomic measurements; Costs; Crystallization; Etching; Fabrication; Paramagnetic resonance; Photovoltaic cells; Semiconductor films; Temperature;
Conference_Titel :
Photovoltaic Specialists Conference, 2002. Conference Record of the Twenty-Ninth IEEE
Print_ISBN :
0-7803-7471-1
DOI :
10.1109/PVSC.2002.1190521
