Author: Peter Neil Morgan
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Metastable Phenomena in Hydrogenated Amorphous Silicon Thin Film Transistors
Threshold Voltage Instability and Relaxation in Hydrogenated Amorphous Silicon Thin Film Transistors [electronic Resource]
Author: Akhavan Fomani, Arash
Publisher: University of Waterloo
ISBN:
Category : Thin film transistors
Languages : en
Pages : 92
Book Description
This thesis presents a study of the bias-induced threshold voltage metastability phenomenon of the hydrogenated amorphous silicon (a-Si:H) thin film transistors (TFTs). An application of gate bias stress shifts the threshold voltage of a TFT. After the bias stress is removed, the threshold voltage eventually returns to its original value. The underlying physical mechanisms for the shift in threshold voltage during the application of the bias and after the removal of the bias stress are investigated. The creation of extra defect states in the band gap of a-Si:H close to the gate dielectric interface, and the charge trapping in the silicon nitride (SiN) gate dielectric are the most commonly considered instability mechanisms of threshold voltage. In the first part of this work, the defect state creation mechanism is reviewed and the kinetics of the charge trapping in the SiN is modelled assuming a simplified mono-energetic and a more realistic Gaussian distribution of the SiN traps. The charge trapping in the mono-energetic SiN traps was approximated by a logarithmic function of time. However, the charge trapping with a Gaussian distribution of SiN traps results in a more complex behavior. The change in the threshold voltage of a TFT after the gate bias has been removed is referred to threshold voltage relaxation, and it is investigated in the second part of this work. A study of the threshold voltage relaxation sheds more light on the metastability mechanisms of a-Si:H TFTs. Possible mechanisms considered for the relaxation of threshold voltage are the annealing of the extra defect states and the charge de-trapping from the SiN gate dielectric. The kinetics of the charge de-trapping from a mono-energetic and a Gaussian distribution of the SiN traps are analytically modelled. It is shown that the defect state annealing mechanisms cannot explain the observed threshold voltage relaxation, but a study of the kinetics of charge de-trapping helps to bring about a very good agreement with the experimentally obtained results. Using the experimentally measured threshold voltage relaxation results, a Gaussian distribution of gap states is extracted for the SiN. This explains the threshold voltage relaxation of TFT after the bias stress with voltages as high as 50V is removed. Finally, the results obtained from the threshold voltage relaxation make it possible to calculate the total charge trapped in the SiN and to quantitatively distinguish between the charge trapping mechanism and the defect state creation mechanisms. In conclusion, for the TFTs used in this thesis, the charge trapping in the SiN gate dielectric is shown to be the dominant threshold voltage metastability mechanism caused in short bias stress times.
Publisher: University of Waterloo
ISBN:
Category : Thin film transistors
Languages : en
Pages : 92
Book Description
This thesis presents a study of the bias-induced threshold voltage metastability phenomenon of the hydrogenated amorphous silicon (a-Si:H) thin film transistors (TFTs). An application of gate bias stress shifts the threshold voltage of a TFT. After the bias stress is removed, the threshold voltage eventually returns to its original value. The underlying physical mechanisms for the shift in threshold voltage during the application of the bias and after the removal of the bias stress are investigated. The creation of extra defect states in the band gap of a-Si:H close to the gate dielectric interface, and the charge trapping in the silicon nitride (SiN) gate dielectric are the most commonly considered instability mechanisms of threshold voltage. In the first part of this work, the defect state creation mechanism is reviewed and the kinetics of the charge trapping in the SiN is modelled assuming a simplified mono-energetic and a more realistic Gaussian distribution of the SiN traps. The charge trapping in the mono-energetic SiN traps was approximated by a logarithmic function of time. However, the charge trapping with a Gaussian distribution of SiN traps results in a more complex behavior. The change in the threshold voltage of a TFT after the gate bias has been removed is referred to threshold voltage relaxation, and it is investigated in the second part of this work. A study of the threshold voltage relaxation sheds more light on the metastability mechanisms of a-Si:H TFTs. Possible mechanisms considered for the relaxation of threshold voltage are the annealing of the extra defect states and the charge de-trapping from the SiN gate dielectric. The kinetics of the charge de-trapping from a mono-energetic and a Gaussian distribution of the SiN traps are analytically modelled. It is shown that the defect state annealing mechanisms cannot explain the observed threshold voltage relaxation, but a study of the kinetics of charge de-trapping helps to bring about a very good agreement with the experimentally obtained results. Using the experimentally measured threshold voltage relaxation results, a Gaussian distribution of gap states is extracted for the SiN. This explains the threshold voltage relaxation of TFT after the bias stress with voltages as high as 50V is removed. Finally, the results obtained from the threshold voltage relaxation make it possible to calculate the total charge trapped in the SiN and to quantitatively distinguish between the charge trapping mechanism and the defect state creation mechanisms. In conclusion, for the TFTs used in this thesis, the charge trapping in the SiN gate dielectric is shown to be the dominant threshold voltage metastability mechanism caused in short bias stress times.
Photo-Induced Metastability in Amorphous Semiconductors
Author: Alexander V. Kolobov
Publisher: John Wiley & Sons
ISBN: 3527608664
Category : Science
Languages : en
Pages : 436
Book Description
A review summarising the current state of research in the field, bridging the gaps in the existing literature. All the chapters are written by world leaders in research and development and guide readers through the details of photo-induced metastability and the results of the latest experiments and simulations not found in standard monographs on this topic. A useful reference not only for graduates but also for scientific and industrial researchers. With a foreword of Kazunobu Tanaka
Publisher: John Wiley & Sons
ISBN: 3527608664
Category : Science
Languages : en
Pages : 436
Book Description
A review summarising the current state of research in the field, bridging the gaps in the existing literature. All the chapters are written by world leaders in research and development and guide readers through the details of photo-induced metastability and the results of the latest experiments and simulations not found in standard monographs on this topic. A useful reference not only for graduates but also for scientific and industrial researchers. With a foreword of Kazunobu Tanaka
Proceedings of the Third Symposium on Thin Film Transistor Technologies
Author: Yue Kuo
Publisher: The Electrochemical Society
ISBN: 9781566771733
Category : Technology & Engineering
Languages : en
Pages : 424
Book Description
Publisher: The Electrochemical Society
ISBN: 9781566771733
Category : Technology & Engineering
Languages : en
Pages : 424
Book Description
Basic Properties of III-V Devices – Understanding Mysterious Trapping Phenomena
Author: Kompa, Günter
Publisher: kassel university press GmbH
ISBN: 3862195414
Category : Compound semiconductors
Languages : en
Pages : 762
Book Description
Trapping effects in III-V devices pose a great challenge to any microwave device modeler. Understanding their physical origins is of prime importance to create physics-related reliable device models. The treatment of trapping phenomena is commonly beyond the classical higher-education level of communication engineers. This book provides any basic material needed to understand trapping effects occurring primarily in GaAs and GaN power HEMT devices. As the text material covers interdisciplinary topics such as crystal defects and localized charges, trap centers and trap dynamics, deep-level transient spectroscopy, and trap centers in passivation layers, the book will be of interest to graduate students of electrical engineering, communication engineering, and physics as well as materials, device, and circuit engineers in research and industry.
Publisher: kassel university press GmbH
ISBN: 3862195414
Category : Compound semiconductors
Languages : en
Pages : 762
Book Description
Trapping effects in III-V devices pose a great challenge to any microwave device modeler. Understanding their physical origins is of prime importance to create physics-related reliable device models. The treatment of trapping phenomena is commonly beyond the classical higher-education level of communication engineers. This book provides any basic material needed to understand trapping effects occurring primarily in GaAs and GaN power HEMT devices. As the text material covers interdisciplinary topics such as crystal defects and localized charges, trap centers and trap dynamics, deep-level transient spectroscopy, and trap centers in passivation layers, the book will be of interest to graduate students of electrical engineering, communication engineering, and physics as well as materials, device, and circuit engineers in research and industry.
The Performance and Stability of Hydrogenated Amorphous Silicon Thin Film Transistors
Amorphous Silicon Technology
Author:
Publisher:
ISBN:
Category : Amorphous semiconductors
Languages : en
Pages : 750
Book Description
Publisher:
ISBN:
Category : Amorphous semiconductors
Languages : en
Pages : 750
Book Description
Amorphous Semiconductors
Author: Kazuo Morigaki
Publisher: John Wiley & Sons
ISBN: 1118757947
Category : Technology & Engineering
Languages : en
Pages : 290
Book Description
Amorphous semiconductors are subtances in the amorphous solid state that have the properties of a semiconductor and which are either covalent or tetrahedrally bonded amorphous semiconductors or chelcogenide glasses. Developed from both a theoretical and experimental viewpoint Deals with, amongst others, preparation techniques, structural, optical and electronic properties, and light induced phenomena Explores different types of amorphous semiconductors including amorphous silicon, amorphous semiconducting oxides and chalcogenide glasses Applications include solar cells, thin film transistors, sensors, optical memory devices and flat screen devices including televisions
Publisher: John Wiley & Sons
ISBN: 1118757947
Category : Technology & Engineering
Languages : en
Pages : 290
Book Description
Amorphous semiconductors are subtances in the amorphous solid state that have the properties of a semiconductor and which are either covalent or tetrahedrally bonded amorphous semiconductors or chelcogenide glasses. Developed from both a theoretical and experimental viewpoint Deals with, amongst others, preparation techniques, structural, optical and electronic properties, and light induced phenomena Explores different types of amorphous semiconductors including amorphous silicon, amorphous semiconducting oxides and chalcogenide glasses Applications include solar cells, thin film transistors, sensors, optical memory devices and flat screen devices including televisions