Browsing by Author "Chu, FT"

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A novel germanium doping method for fabrication of high-performance p-channel poly-Si1-xGex TFT by excimer laser crystallization
(2003-04-01)
Chang, TK
;
Chu, FT
;
Lin, CW
;
Tseng, CH
;
Cheng, HC
In this letter, a novel process for fabricating p-channel poly-Si1-xGex thin-film transistors (TFTs) with high-hole mobility was demonstrated. Germanium (Ge) atoms were incorporated into poly-Si by excimer laser irradiation of a-Si1-xGex/poly-Si double layer. For small size TFTs, especially when channel width/length (W/L) was less than 2 mum/2 mum, the hole mobility of poly-Si1-xGex TFTs was superior to that of poly-Si TFTs. It was inferred that the degree of mobility enhancement by Ge incorporation was beyond that of mobility degradation by defect trap generation when TFT size was shrunk to 2 mum/2 mum. The poly-Si0.91Ge0.09 TFT exhibited a high-hole mobility of 112 cm(2)/V-s, while the hole mobility of the poly-Si counterpart was 73 cm(2)/V-s.
An investigation of bias temperature instability in hydrogenated low-temperature polycrystalline silicon thin film transistors
(2002-09-01)
Lin, CW
;
Tseng, CH
;
Chang, TK
;
Chang, YH
;
Chu, FT
The instability mechanisms of the hydrogenated n-channel low-temperature polycrystalline silicon thin film transistors under on-state stress were investigated with various bias stress conditions and device channel widths. It was found that hot carrier degradation which originated from a high drain electric field and self-heating during high current operation were the two dominant mechanisms responsible for device degradation. An electrically reversible depassivation/passivation phenomenon was also found in devices under high current stress. but not in those under hot carrier stress. It was inferred that the self-heating effect would accelerate the bond breakage and diffusion of hydrogen ions, thus enhancing the rate of depassivation/passivation. Moreover. when the Current in the hot carrier stress mode was sufficiently high. self-heating became the dominant degradation mechanism and hot carrier degradation phenomenon was also suppressed for devices with large channel width, Meanwhile, the electrically reversible depassivation/passivation phenomenon also occurred in this case.
Correlation between transmission-line-pulsing I-V curve and human-body-model ESD level on low temperature poly-Si TFT devices
(2004)
Ker, MD
;
Hou, CL
;
Chang, CY
;
Chu, FT
;
電機學院
The relations between human-body-model (HBM) electrostatic discharge (ESD) waveform and transmission line pulsing (TLP) I-V curve on low temperature poly-Si (LTPS) thin film transistor (TFT) have been investigated in this paper. By using ESD zapper and TLP system, the ESD waveforms and TLP I-V curves on the LPTS TFT devices under different device dimensions have been measured. From the experimental results, the turn-on resistances of TFT devices during HBM zapping and TLP stress are almost the same. Such experimental results have shown a good correction between HBM ESD level and TLP measurement on LTPS TFT devices.
Investigation of inductively coupled plasma gate oxide on low temperature polycrystalline-silicon TFTs
(2002-06-01)
Tseng, CH
;
Chang, TK
;
Chu, FT
;
Shieh, JM
;
Dai, BT
By optimizing the inductively coupled plasma (ICP) oxidation condition, a thin oxide of 10 nm has been grown at 350degreesC to achieve excellent gate oxide integrity of low leakage current < 5x10(-8) A/cm(2) (at 8 MV/cm), high breakdown field of 9.3 MV/cm and low interface trap density of 1.5x10(11)/eV cm(2). The superior performance poly-Si TFTs using such a thin ICP oxide were attained to achieve a high ON current of 110 μA/μm at V-D=1 V and V-G = 5 V and the high electron field effect mobility of 231 cm(2)/V.S.
Thickness dependence of microstructure of laterally crystallized poly-Si thin films and electrical characteristics of low-temperature poly-Si TFTs
(2003-08-01)
Chang, TK
;
Lin, CW
;
Chang, YH
;
Tseng, CH
;
Chu, FT
The effects of thickness of a-Si thin films on the resulting microstructure of metal-induced laterally crystallized (MILC) poly-Si and electrical characteristics of MILC low temperature poly-Si (LTPS) thin film transistors (TFTs) were investigated. The TEM images revealed a double-layer structure in the 1000-Angstrom MILC poly-Si thin film. However, for the 400-Angstrom MILC poly-Si thin film, there were single-layer grains within the thin film layer. The reason has been ascribed to the geometry restriction in the crystallization procedure. The average mobility of fabricated MILC LTPS TFTs with active layer thickness of 400 Angstrom showed a little higher than that with 1000 Angstrom active layer. Moreover, the MILC LTPS TFTs with active layer thickness of 400 Angstrom exhibited better electrical uniformity than those with 1000 Angstrom active layer either in threshold voltage or field-effect mobility. The reason should also be attributed to the different crystalline structures within the two thin-film layers. (C) 2003 The Electrochemical Society.