Title :
p-channel amorphous silicon TFTs with high hole mobility
Author :
Oda, Shoichiro ; Adachi, N. ; Katoh, S. ; Matsumura, Mieko
Author_Institution :
Tokyo Inst. of Technol.
fDate :
12/1/1988 12:00:00 AM
Abstract :
The authors have fabricated p-channel FETs using a-Si:H(F) films, to demonstrate the high hole mobility of a-Si:H(F) in these devices as well as to investigate the feasibility of a-Si CMOS devices. To prepare high-quality a-Si films, a glow discharge of a gaseous mixture of SiF 4 and H2 was used as a deposition precursor, and the residence time of the reactants was varied carefully for the preparation of relevant radicals. The authors fabricated a prototype p-channel MOSFET with a staggered electrode structure consisting of a 100 nm layer of a-Si:H(F), a 200-nm layer of CVD (chemical-vapor-deposited) SiO2, and an evaporated-Cr film for source-drain and gate electrodes. In the final step, the device was annealed in H2 for 30 min at 250°C. The field-effect mobility for holes deduced from transistor characteristics was 0.12 cm 2/V-s, about two orders higher than that of conventional p-channel a-Si FETs. An off-resistance/on-resistance ratio higher than 5000 has been obtained. The electron mobility was 0.24 cm2/V-s
Keywords :
CVD coatings; amorphous semiconductors; carrier mobility; elemental semiconductors; fluorine; hydrogen; insulated gate field effect transistors; silicon; thin film transistors; 100 nm; 200 nm; CVD deposited SiO2; H2; MOSFET; Si:H, F-SiO2-Cr; SiF4; TFT; a-Si CMOS devices; annealing; chemical-vapor-deposited; elemental semiconductors; evaporated-Cr film; field-effect mobility; gaseous mixture; glow discharge; high hole mobility; p-channel FETs; staggered electrode structure; thin film transistors; Amorphous silicon; Annealing; Chemical vapor deposition; Electrodes; Electron mobility; FETs; Glow discharges; MOSFET circuits; Prototypes; Thin film transistors;
Journal_Title :
Electron Devices, IEEE Transactions on
