Hot-Wire Deposited Amorphous Silicon Thin-Film Transistors

1996 ◽  
Vol 424 ◽  
Author(s):  
R. E. I. Schropp ◽  
K. F. Feenstra ◽  
C. H. M. Van Der Werf ◽  
J. Holleman ◽  
H. Meiling
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Thin Film Transistors ◽  
Gate Dielectric ◽  
Chemical Vapor ◽  
Current Crowding ◽  
Hot Wire ◽  
Saturation Regime ◽  
Silicon Thin Film ◽  
Order Of Magnitude

AbstractWe present the first thin film transistors (TFTs) incorporating a low hydrogen content (5 - 9 at.-%) amorphous silicon (a-Si:H) layer deposited by the Hot-Wire Chemical Vapor Deposition (HWCVD) technique. This demonstrates the possibility of utilizing this material in devices. The deposition rate by Hot-Wire CVD is an order of magnitude higher than by Plasma Enhanced CVD. The switching ratio for TFTs based on HWCVD a-Si:H is better than 5 orders of magnitude. The field-effect mobility as determined from the saturation regime of the transfer characteristics is still quite poor. The interface with the gate dielectric needs further optimization. Current crowding effects, however, could be completely eliminated by a H2 plasma treatment of the HW-deposited intrinsic layer. In contrast to the PECVD reference device, the HWCVD device appears to be almost unsensitive to bias voltage stressing. This shows that HW-deposited material might be an approach to much more stable devices.

Hot-Wire Deposited Amorphous Silicon Thin-Film Transistors

1996 ◽  
Vol 420 ◽  
Author(s):  
R. E. I. Schropp ◽  
K. F. Feenstra ◽  
C. H. M. Van Der Werf ◽  
J. Holleman ◽  
H. Meiling
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Thin Film Transistors ◽  
Gate Dielectric ◽  
Chemical Vapor ◽  
Current Crowding ◽  
Hot Wire ◽  
Saturation Regime ◽  
Silicon Thin Film ◽  
Order Of Magnitude

AbstractWe present the first thin film transistors (TFTs) incorporating a low hydrogen content (5 - 9 at.-%) amorphous silicon (a-Si:H) layer deposited by the Hot-Wire Chemical Vapor Deposition (HWCVD) technique. This demonstrates the possibility of utilizing this material in devices. The deposition rate by Hot-Wire CVD is an order of magnitude higher than by Plasma Enhanced CVD. The switching ratio for TFTs based on HWCVD a-Si:H is better than 5 orders of magnitude. The field-effect mobility as determined from the saturation regime of the transfer characteristics is still quite poor. The interface with the gate dielectric needs further optimization. Current crowding effects, however, could be completely eliminated by a H2 plasma treatment of the HW-deposited intrinsic layer. In contrast to the PECVD reference device, the HWCVD device appears to be almost unsensitive to bias voltage stressing. This shows that HW-deposited material might be an approach to much more stable devices.

Hot-wire CVD a-Si:H TFT on Plastic Substrates

2006 ◽  
Vol 910 ◽  
Author(s):  
Farhad Taghibakhsh ◽  
K.S. Karim
Keyword(s):  
Thin Film ◽  
Chemical Vapor Deposition ◽  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Thin Film Transistors ◽  
Gate Dielectric ◽  
Chemical Vapor ◽  
Plastic Substrate ◽  
Hot Wire ◽  
Low Leakage

AbstractFabrication of hot-wire chemical vapor deposition (HWCVD) of amorphous silicon (a-Si) thin film transistors (TFT) on thin polyamide sheets is reported. A single graphite filament at 1500 °C was used for HWCVD and device quality amorphous silicon films were deposited with no thermal damage to plastic substrate. Top-gate staggered thin film transistors (TFTs) were fabricated at 150°C using hot-wire deposited a-Si channel, Plasma enhanced chemical vapor deposition (PECVD) silicon nitride gate dielectric, and microcrystalline n+ drain/source contacts. Low leakage current of 5×10-13 A, high switching current ratio of 1.3×107, and small sub threshold swing of 0.3 V/dec was obtained for TFTs with aspect ratio of 1300μm/100μm. The field effect mobility was extracted to be 0.34 cm2/V.s.

Amorphous Silicon Thin-Film Transistors with a Hot-Wire Active-Layer Deposited at High Growth Rate

1997 ◽  
Vol 467 ◽  
Author(s):  
V. Chu ◽  
J. Jarego ◽  
H. Silva ◽  
T. Silva ◽  
M. Boucinha ◽  
...  
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Active Layer ◽  
Thin Film Transistors ◽  
Chemical Vapor ◽  
High Growth ◽  
Dark Conductivity ◽  
High Growth Rate ◽  
Hot Wire ◽  
Silicon Thin Film

ABSTRACTHigh-quality thin film transistors (TFT) with hydrogenated amorphous silicon (a-Si:H) deposited by hot-wire (HW) chemical vapor deposition as the active layer at growth rates above 20 Å/s are compared to TFTs with a-Si:H deposited by RF glow discharge at 1 Å/s. The subgap absorption measured by the constant photocurrent method and steady-state photoconductivity measured between source and drain are used to characterize the a-Si:H in the TFT. The activation energy of the dark conductivity is measured as a function of the gate voltage to obtain the position of the Fermi level. The effect of a bias stress on the TFT transfer curve is obtained.

Low frequency noise in amorphous silicon thin film transistors with SiNx gate dielectric

2009 ◽  
Vol 105 (12) ◽  
pp. 124504 ◽  
Author(s):  
S. L. Rumyantsev ◽  
Sung Hun Jin ◽  
M. S. Shur ◽  
Mun-Soo Park
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Thin Film Transistors ◽  
Gate Dielectric ◽  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Silicon Thin Film

Investigation of the off-current in amorphous silicon thin film transistors for SiO2 and SiNx. gate insulators

1996 ◽  
Vol 424 ◽  
Author(s):  
Jeong Hyun Kim ◽  
Woong Sik Choi ◽  
Chan Hee Hong ◽  
Hoe Sup Soh
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Thin Film Transistors ◽  
Chemical Vapor ◽  
Interface State ◽  
State Density ◽  
Gate Insulator ◽  
Defect States ◽  
Silicon Thin Film ◽  
Pressure Chemical

AbstractThe off current behavior of hydrogenated amorphous silicon (a-Si:H) thin film transistors (TFTs) with an atmospheric pressure chemical vapor deposition (APCVD) silicon dioxide (SiO2) gate insulator were investigated at negative gate voltages. The a-Si:H TFT with SiO2 gate insulator has small off currents and large activation energy (Ea) of the off current compared to the a-Si:H TFT with SiNx gate insulator. The holes induced in the channel by negative gate voltage seem to be trapped in the defect states near the a-Si:H/SiO2 interface. The interface state density in the lower half of the band gap of a-Si:H/SiO2 appears to be much higher than that for a-Si:H/SiNx.

Carrier Transport in Polycrystalline and Amorphous Silicon Thin Film Transistors

1994 ◽  
Vol 358 ◽  
Author(s):  
T. Sameshima ◽  
M. Sekiya ◽  
M. Hara ◽  
N. Sano ◽  
A. Kohno
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Thin Film Transistors ◽  
Carrier Transport ◽  
Defect Density ◽  
Inversion Layer ◽  
Chemical Vapor ◽  
Laser Crystallization ◽  
Silicon Thin Film ◽  
Plasma Chemical Vapor Deposition

ABSTRACTThe technologies of laser crystallization and methods of SiO2 formation in remote plasma chemical vapor deposition or SiO evaporation with an oxygen ambient realize the fabrication of n-channel polycrystalline and amorphous silicon thin film transistors (poly-Si and a-Si TFTs) at a temperature lower than 300 °C. The defect density was achieved to be 2∼3×1011 cm−2eV−1 and threshold voltage was about IV for both TFTs. The maximum field effect mobility was 600 cm2/Vs for poly-Si TFTs and 2.6 cm2/Vs for a-Si TFTs. The mobility of poly-Si TFT decreased as the gate voltage increases. This is interpreted as that the electrons are confined in the narrow inversion layer and electron scattering with phonon is enhanced for higher normal electric field.

scholarly journals A Comparison between Thin-Film Transistors Deposited by Hot-Wire Chemical Vapor Deposition and PECVD

10.30544/128 ◽  
2015 ◽  
Vol 21 (1) ◽  
pp. 7-14
Author(s):  
Meysam Zarchi ◽  
Shahrokh Ahangarani
Keyword(s):  
Thin Film ◽  
Chemical Vapor Deposition ◽  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Thin Film Transistors ◽  
Chemical Vapor ◽  
Silicon Films ◽  
Intrinsic Stress ◽  
Hot Wire ◽  
Microcrystalline Silicon

The effect of new growth techniques on the mobility and stability of amorphous silicon (a-Si:H) thin film transistors (TFTs) has been studied. It was suggested that the key parameter controlling the field-effect mobility and stability is the intrinsic stress in the a-Si:H layer. Amorphous and microcrystalline silicon films were deposited by radiofrequency plasma enhanced chemical vapor deposition (RF-PECVD) and hot-wire chemical vapor deposition (HW-CVD) at 100 ºC and 25 ºC. Structural properties of these films were measured by Raman Spectroscopy. Electronic properties were measured by dark conductivity, σd, and photoconductivity, σph. For amorphous silicon films deposited by RF-PECVD on PET, photosensitivity's of >105 were obtained at both 100 º C and 25 ºC. For amorphous silicon films deposited by HW-CVD, a photosensitivity of > 105 was obtained at 100 ºC. Microcrystalline silicon films deposited by HW-CVD at 95% hydrogen dilution show σph~ 10-4 Ω-1cm-1, while maintaining a photosensitivity of ~102 at both 100 ºC and 25 ºC. Microcrystalline silicon films with a large crystalline fraction (> 50%) can be deposited by HW-CVD all the way down to room temperature.

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