Effects of Hydrogenation on the Off-State of Polysilicon Thin Film Transistors

1987 ◽  
Vol 106 ◽  
Author(s):  
Babar A. Khan ◽  
Ranjana Pandya
Keyword(s):  
Thin Film ◽  
Thin Film Transistors ◽  
Recombination Center ◽  
Dangling Bond ◽  
Band Tail ◽  
Carrier Generation ◽  
Bond Density ◽  
Transient Photoconductivity ◽  
Spin Resonance ◽  
Center Density

ABSTRACTWe have carried out transient photoconductivity experiments on hydrogenated and unhydrogenated polysilicon Thin Film Transistors (TFTs) which indicate that the primary effect of plasma hydrogenation is the reduction by several orders of magnitude of the band tail trapping states. A smaller effect is a reduction of the dangling bond density by a factor of 2 or 3 as indicated by Electron Spin Resonance (ESR) measurements. Since the dangling bond is associated with the generation/recombination center, it may not be obvious how such a small reduction in generation/recombination center density leads to over 2 orders of magnitude reduction in off-state current of the TFTs. In this paper, we describe how the large reduction of band tail states can lead to significant reduction of carrier generation near the contacts despite the fact that the generation/recombination center density is not changed significantly. This reduction of carrier generation leads to the observed reduction in off-state currents.

Defect and Tail States in Microcrystalline Silicon investigated by pulsed ESR

2000 ◽  
Vol 609 ◽  
Author(s):  
P. Kanschat ◽  
H. Mell ◽  
K. Lips ◽  
W. Fuhs
Keyword(s):  
Electron Spin Resonance ◽  
Detailed Analysis ◽  
Electron Spin ◽  
Qualitative Model ◽  
Dangling Bond ◽  
Microcrystalline Silicon ◽  
Band Tail ◽  
Spin Resonance ◽  
Donor States ◽  
Broad Structure

ABSTRACTWe report on a detailed analysis of paramagnetic states in a doping series of microcrystalline silicon, μc-Si:H, by pulsed electron spin resonance. We identify two dangling bond like structures at g = 2.0052 (db1) and g = 2.0043 (db2). Whereas db1 is evenly distributed in the gap, the db2 state is found to be localized in the lower part of the gap. The CE resonance at g ≈ 1.998 is assigned to electrons in conduction band tail states. In p-doped samples, we observe a broad structure CH at g ≈ 2.08 which we identify with holes trapped in valence band tail states. It is shown that the CH state behaves very similar on illumination as the CE resonance. In n-type samples a pair of hyperfine split lines (A ≈ 11 mT) is found which apparently does not originate from 31P-donor states. On the basis of our results we propose a qualitative model for paramagnetic states in μc-Si:H.

scholarly journals Analysis of carrier transport and band tail states in p-type tin monoxide thin-film transistors by temperature dependent characteristics

2016 ◽  
Vol 108 (26) ◽  
pp. 263503 ◽  
Author(s):  
Jiawei Zhang ◽  
Xi Kong ◽  
Jia Yang ◽  
Yunpeng Li ◽  
Joshua Wilson ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Film Transistors ◽  
Carrier Transport ◽  
Temperature Dependent ◽  
Band Tail ◽  
P Type ◽  
Tin Monoxide

Dangling-bond defect state creation in microcrystalline silicon thin-film transistors

2000 ◽  
Vol 77 (5) ◽  
pp. 750-752 ◽  
Author(s):  
R. B. Wehrspohn ◽  
M. J. Powell ◽  
S. C. Deane ◽  
I. D. French ◽  
P. Roca i Cabarrocas
Keyword(s):  
Thin Film ◽  
Thin Film Transistors ◽  
Defect State ◽  
Dangling Bond ◽  
Microcrystalline Silicon ◽  
Silicon Thin Film ◽  
State Creation

scholarly journals Material Parameters in a Thick Hydrogenated Amorphous Silicon Detector and their Effect on Signal Collection

1989 ◽  
Vol 149 ◽  
Author(s):  
S. Qureshi ◽  
V. Perez-Mendez ◽  
S. N. Kaplan ◽  
I. Fujieda ◽  
G. Cho
Keyword(s):  
Amorphous Silicon ◽  
Defect Density ◽  
Hydrogenated Amorphous Silicon ◽  
Silicon Detector ◽  
Dangling Bond ◽  
Material Parameters ◽  
Bond Density ◽  
Transient Photoconductivity ◽  
Signal Collection ◽  
Hydrogenated Amorphous

ABSTRACTTransient photoconductivity and ESR measurements were done to relate the ionized dangling bond density and the spin density of thick hydrogenated amorphous silicon (a-Si:H) detectors. We found that only a fraction (∼30–35%) of the total defect density as measured by ESR is ionized when the detector is biased into deep depletion. The measurements on annealed samples also show that this fraction is about 0.3. An explanation based on the shift of the Fermi energy is given. The measurements show that the time dependence of relaxation is a stretched exponential.

Steady State and Transient Photoconductivity of Thin Film Polydiacetylene Single Crystals

1990 ◽  
Vol 214 ◽  
Author(s):  
Y. Yang ◽  
J. Y. Lee ◽  
P. Miller ◽  
L. Li ◽  
J. Kumar ◽  
...  
Keyword(s):  
Thin Film ◽  
Steady State ◽  
Single Crystals ◽  
Drift Velocity ◽  
Incident Light ◽  
Light Polarization ◽  
Transport Mechanisms ◽  
Carrier Generation ◽  
Electric Field Dependence ◽  
Transient Photoconductivity

ABSTRACTCharge carrier generation and transport mechanisms in polydiacetylene thin film single crystals., poly-PTS (2,4-hexadiyne-1,6-diol bis(p-toluenesulfonate)) and poly- BTFP (bis-(4-n-butyl-2,3,5,6-tetra-fluorophenyl) butadiyne), are studied by using steady state and transient photoconductivity techniques. The electric field dependence of the steady state photocurrent is superlinear for both samples. Dependence of photocurrent on incident light polarization has been investigated. The polarization dependence of photocurrent has completely different behavior for the polydiacetylene PTS and BTFP. Single-gap transmission line experiment has been designed to directly measure the drift velocity of PTS single crystals. A drift velocity of the order of 106cm/s was measured.

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