Temperature and Frequency Dependent Characteristics of Amorphous Silicon thin film Transistors

1995 ◽  
Vol 377 ◽  
Author(s):  
H. C. Slade ◽  
M. S. Shur ◽  
M. Hack
Keyword(s):  
Thin Film ◽  
Temperature Dependence ◽  
Amorphous Silicon ◽  
Thin Film Transistors ◽  
Field Effect ◽  
Experimental Studies ◽  
Localized States ◽  
Field Effect Mobility ◽  
Silicon Thin Film ◽  
Capacitance Voltage

ABSTRACTOn the basis of our experimental studies of the temperature dependence of amorphous silicon thin film transistor current-voltage and capacitance-voltage characteristics, we have developed an analytical device model suitable for implementation in circuit simulators. This model describes the above-threshold (on) current and the subthreshold (off) current [1]. In addition, the model is able to incorporate changes in the distribution of localized states which arise from thermal and/or bias stress. In this paper, we identify the temperature-dependent parameters, which describe the temperature dependence of both the on and off currents, and we model the leakage current at large negative gate biases. The modeling results are in good agreement with our experimental data. We also discuss capacitance-voltage characteristics of amorphous silicon thin film transistors for varying gate lengths, temperatures, and frequencies. The measured capacitance-voltage characteristics show strong frequency dispersion, which is related to the trap-limited transport of carriers in the channel. The characteristic time constant, which determines when the channel capacitance becomes dependent on frequency, is on the order of the transit time calculated with the field-effect mobility and the electric field. The field-effect mobility takes into account carrier trapping by the localized states and is a function of gate voltage and temperature.

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.

Studies of the Stability of Amorphous Silicon Thin Film Transistors

1992 ◽  
Vol 258 ◽  
Author(s):  
T. Globus ◽  
M. Shur ◽  
M. Hack
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Leakage Current ◽  
Thin Film Transistors ◽  
Experimental Studies ◽  
Gate Insulator ◽  
Localized States ◽  
Silicon Thin Film ◽  
Insulator Layer ◽  
Voltage Stress

ABSTRACTOur experimental studies confirm that changes in a-Si Thin Film Transistors (TFTs) under voltage stress occur in the device channel and not in the contacts. We demonstrate that stressing an a-Si TFT not only shifts the device threshold voltage but can also changes the slope of the semilog subthreshold current dependence on the gate voltage. In addition, stressing can decrease the minimum leakage current. The creation of new localized states in the amorphous silicon under voltage stress qualitatively explains all these effects, while carrier tunneling and trapping in the gate insulator layer cannot by itself explain our data. At large negative gate voltages, the leakage current increases due to the holes injected into the channel. This hole current is also affected by voltage stress as can be predicted by the state creation mechanism.

Temperature Dependence of Field-Effect Mobility in Organic Thin-Film Transistors: Similarity to Inorganic Transistors

2016 ◽  
Vol 16 (4) ◽  
pp. 3219-3222 ◽  
Author(s):  
Jun Okada ◽  
Takashi Nagase ◽  
Takashi Kobayashi ◽  
Hiroyoshi Naito
Keyword(s):  
Thin Film ◽  
Temperature Dependence ◽  
Thin Film Transistors ◽  
Field Effect ◽  
Carrier Transport ◽  
Organic Thin Film Transistors ◽  
Localized States ◽  
Organic Thin Film ◽  
Field Effect Mobility ◽  
Oxide Semiconductors

Carrier transport in solution-processed organic thin-film transistors (OTFTs) based on dioctylben-zothienobenzothiophene (C8-BTBT) has been investigated in a wide temperature range from 296 to 10 K. The field-effect mobility shows thermally activated behavior whose activation energy becomes smaller with decreasing temperature. The temperature dependence of field-effect mobility found in C8-BTBT is similar to that of others materials: organic semiconducting polymers, amorphous oxide semiconductors and hydrogenated amorphous silicon. These results indicate that hopping transport between isoenergetic localized states becomes dominated in a low temperature regime in these materials.

Amorphous Silicon Thin Film Transistors With High Electron Field Effect Mobility

1992 ◽  
Vol 258 ◽  
Author(s):  
J.L. Andújar ◽  
E. Bertrán ◽  
A. Canillas ◽  
J. Campmany ◽  
J. Cifre
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Thin Film Transistors ◽  
Field Effect ◽  
Rf Plasma ◽  
High Electron ◽  
Field Effect Mobility ◽  
Silicon Thin Film ◽  
Insulator Layer ◽  
Electron Field

ABSTRACTNormal staggered hydrogenated amorphous silicon (a-Si:H) thin film transistors (TFT) were prepared by rf plasma deposition through a three-step process. The TFTs were constituted by an a-SiN/a-Si:H structure grown on NiCr source-drain electrodes evaporated on glass substrates. The intrinsic a-Si:H active layer (Fermi level at EC-EF = 0.7 eV) was deposited from pure SiH4 rf plasma, and the insulator layer of a-SiN was grown using a high rf power plasma (200 mW/cm2) of SiH4-N2 mixture with a SiH4 fraction of 0.5 %. Ellipsometric measurements showed that a very transparent a-SiN film was grown with an abrupt interface insulator/a-Si:H. TFTs with 0.2 μm thick a-Si:H layer and 10 μm channel length have on-off current ratios of 5 104, electron field effect mobility of 1.5 cm2/V-s (dielectric constant εri ≈ 7.9), and threshold voltage around 5 V. The results are discussed in terms of low hydrogen content and low porosity of these a-SiN films prepared from silane-nitrogen.

Field-effect mobility of amorphous silicon thin-film transistors under strain

2004 ◽  
Vol 338-340 ◽  
pp. 732-735 ◽  
Author(s):  
H. Gleskova ◽  
P.I. Hsu ◽  
Z. Xi ◽  
J.C. Sturm ◽  
Z. Suo ◽  
...  
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Thin Film Transistors ◽  
Field Effect ◽  
Field Effect Mobility ◽  
Silicon Thin Film
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