TY - GEN
T1 - Amorphous silicon crystallization for TFT applications
AU - Yi, J.
AU - Wallace, R.
AU - Sridhar, N.
AU - Chung, D. D.L.
AU - Anderson, W. A.
PY - 1994
Y1 - 1994
N2 - Thin film hydrogenated amorphous silicon (a-Si:H) was deposited on molybdenum (Mo) substrates by d.c. glow discharge. We investigated the a-Si:H crystallization using four anneal techniques; nitrogen atmosphere furnace, vacuum, rapid thermal anneal (RTA), and excimer laser anneal. Anneal temperature ranged from 100 to 1200 °C. Excimer laser energy per pulse ranged from 90 to 340 mJ. Transmission electron microscopy (TEM) revealed microstructure of crystallized Si film with grain size over 0.5 μm. X-ray diffraction (XRD) and Raman spectroscopy were employed to determine the degree of crystallization. The a-Si:H started to crystallize at temperatures over 600 °C. An 850 °C anneal reduced film resistivity to 105 (Ω-cm) for intrinsic and 1 (Ω-cm) for n-type. Coplanar type thin film transistors (TFT) with gate channel length of 25 μm and width of 220 μm were fabricated with various insulating layers; rf sputtered SiO2, Si3N4, BaTiO3, MgO, and evaporated SiO. The first two exhibited the least leakage current. The as-grown intrinsic a-Si:H field effect mobility was around 0.03 (cm2V.s) and delay time was 5×10-7 s. The solid phase crystallized silicon film exhibited high leakage current. The delay time of an excimer laser anneal treated TFT was reduced to 2.5×10-7 s. Crystallized Si film mobility was improved to 15 (cm2/V.s).
AB - Thin film hydrogenated amorphous silicon (a-Si:H) was deposited on molybdenum (Mo) substrates by d.c. glow discharge. We investigated the a-Si:H crystallization using four anneal techniques; nitrogen atmosphere furnace, vacuum, rapid thermal anneal (RTA), and excimer laser anneal. Anneal temperature ranged from 100 to 1200 °C. Excimer laser energy per pulse ranged from 90 to 340 mJ. Transmission electron microscopy (TEM) revealed microstructure of crystallized Si film with grain size over 0.5 μm. X-ray diffraction (XRD) and Raman spectroscopy were employed to determine the degree of crystallization. The a-Si:H started to crystallize at temperatures over 600 °C. An 850 °C anneal reduced film resistivity to 105 (Ω-cm) for intrinsic and 1 (Ω-cm) for n-type. Coplanar type thin film transistors (TFT) with gate channel length of 25 μm and width of 220 μm were fabricated with various insulating layers; rf sputtered SiO2, Si3N4, BaTiO3, MgO, and evaporated SiO. The first two exhibited the least leakage current. The as-grown intrinsic a-Si:H field effect mobility was around 0.03 (cm2V.s) and delay time was 5×10-7 s. The solid phase crystallized silicon film exhibited high leakage current. The delay time of an excimer laser anneal treated TFT was reduced to 2.5×10-7 s. Crystallized Si film mobility was improved to 15 (cm2/V.s).
UR - https://www.scopus.com/pages/publications/0028312758
M3 - Conference contribution
AN - SCOPUS:0028312758
SN - 1558992200
T3 - Materials Research Society Symposium Proceedings
SP - 701
EP - 706
BT - Crystallization and Related Phenomena in Amorphous Materials
A2 - Libera, Matthew
A2 - Haynes, Tony E.
A2 - Cebe, Peggy
A2 - Dickinson Jr., James E.
PB - Publ by Materials Research Society
T2 - Proceedings of the 1993 Fall Meeting of the Materials Research Society
Y2 - 29 November 1993 through 2 December 1993
ER -