Switch-On Transients And Static Characteristics Of Polymorphous And Amorphous Silicon Thin-Film Transistor

2003 ◽  
Vol 762 ◽  
Author(s):  
V. Tripathi ◽  
Y. N. Mohapatra
Keyword(s):  
Thin Film ◽  
Electrical Properties ◽  
Amorphous Silicon ◽  
Thin Film Transistor ◽  
Chemical Vapor ◽  
Localized States ◽  
Silicon Thin Film ◽  
Hydrogen Dilution ◽  
Order Of Magnitude ◽  
Switching Characteristics

AbstractHydrogenated polymorphous silicon (Pm-Si:H) being an admixture of amorphous and ordered phase silicon shows improved optical and electrical properties due to the presence of nanocrystallites. In order to compare the dynamic and steady state electrical properties in a-Si:H and pm-Si:H, bottom gate Thin Film Transistors (TFT) of these materials were fabricated with SiO2 as the insulating layer. The active materials were deposited using plasma-enhanced chemical vapor deposition (PECVD) by varying pressure, temperature and hydrogen dilution. Transfer characteristics of TFTs made using pm-Si:H show lower leakage current, higher on-current and sharper volt per decade change as compared to similar TFTs made from a-Si:H. Density of states in pm-Si:H as calculated from field effect conductance using incremental method is observed to be an order of magnitude lower than in a-Si:H based devices. To compare dynamic characteristics, we studied the switch-on transient characteristics of polymorphous and amorphous silicon TFTs by pulsing the gate to different voltages in the temperature range of 150-300K. The switch-on transients are trap limited with overall better switching characteristics for pm-Si:H samples. An initial rising transient in case of pm-Si:H is activated with an effective energy of 0.3 eV. The origins of transients are interpreted in terms of trap limited carrier dynamics and charge redistribution within the distribution of localized states.

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.

Influence of Hydrogen Dilution on Electrical Properties of Amorphous Silicon Thin Films Deposited on Glass Substrates

2011 ◽  
Vol 221 ◽  
pp. 117-122
Author(s):  
Ying Ge Li ◽  
Dong Xing Du
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electrical Properties ◽  
Amorphous Silicon ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Thin Layers ◽  
Glass Substrates ◽  
Silicon Thin Films ◽  
Hydrogen Dilution

Thin film Amorphous Silicon materials have found wide application in photovoltaic industry. In this paper, thin layers (around 300nm) of intrinsic hydrogenated amorphous silicon (a-Si:H) are fabricated on glass (Corning Eagle2000TM) substrates by employing plasma enhanced chemical vapor deposition (PECVD) system with gas sources of silane and hydrogen. The deposited thin films are proven to be material of amorphous silicon by Raman spectroscopy measurement and their electronic transport properties are thoroughly characterized in terms of photoconductivity, dark conductivity and photo response. The effect of Hydrogen dilution on electrical properties are investigated for a-Si:H thin films deposited in the temperatures range of 150~200°C. Results indicate that a-Si:H thin films on glass substrate owns device-quality electrical properties and could be applied on fabricating thin film solar cells as the absorber layer material and on other photovoltaic or photo electronic devices.

Amorphous-silicon thin film transistor with two-step exposure process

2000 ◽  
Author(s):  
Pi-Fu Chen ◽  
Jr-Hong Chen ◽  
Dou-I Chen ◽  
HsixgJu Sung ◽  
June-Wei Hwang ◽  
...  
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Thin Film Transistor ◽  
Silicon Thin Film ◽  
Exposure Process

Hydrogenation Effect of Amorphous Silicon Thin Film Transistors by Atmospheric Pressure CVD

1993 ◽  
Vol 297 ◽  
Author(s):  
Byung Chul Ahn ◽  
Jeong Hyun Kim ◽  
Dong Gil Kim ◽  
Byeong Yeon Moon ◽  
Kwang Nam Kim ◽  
...  
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Atmospheric Pressure ◽  
Thin Film Transistors ◽  
Field Effect ◽  
Low Cost ◽  
Thin Film Transistor ◽  
Field Effect Mobility ◽  
Silicon Thin Film ◽  
Hydrogenation Effect

The hydrogenation effect was studied in the fabrication of amorphous silicon thin film transistor using APCVD technique. The inverse staggered type a-Si TFTs were fabricated with the deposited a-Si and SiO2 films by the atmospheric pressure (AP) CVD. The field effect mobility of the fabricated a-Si TFT is 0.79 cm2/Vs and threshold voltage is 5.4V after post hydrogenation. These results can be applied to make low cost a-Si TFT array using an in-line APCVD system.

A Center-Offset Polycrystalline-Silicon Thin-Film Transistor With ${\rm n}^{+}$ Amorphous-Silicon Contacts

2009 ◽  
Vol 30 (1) ◽  
pp. 36-38 ◽  
Author(s):  
J. H. Oh ◽  
D. H. Kang ◽  
W. H. Park ◽  
J. Jang ◽  
Y. J. Chang ◽  
...  
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Polycrystalline Silicon ◽  
Thin Film Transistor ◽  
Silicon Thin Film

Study on Light Induced Leakage Current Related to Amorphous Silicon TFT Design

2007 ◽  
Vol 124-126 ◽  
pp. 259-262
Author(s):  
Jae Hong Jeon ◽  
Kang Woong Lee
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Leakage Current ◽  
Thin Film Transistor ◽  
Silicon Layer ◽  
Gate Electrode ◽  
Silicon Thin Film ◽  
Pattern Design ◽  
Conventional Design ◽  
The One

We investigated the effect of amorphous silicon pattern design regarding to light induced leakage current in amorphous silicon thin film transistor. In addition to conventional design, where amorphous silicon layer is protruding outside the gate electrode, we designed and fabricated amorphous silicon thin film transistors in another two types of bottom gated structure. The one is that the amorphous silicon layer is located completely inside the gate electrode and the other is that the amorphous silicon layer is protruding outside the gate electrode but covered completely by the source and drain electrode. Measurement of the light induced leakage current caused by backlight revealed that the design where the amorphous silicon is located inside the gate electrode was the most effective however the last design was also effective in reducing the leakage current about one order lower than that of the conventional design.

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