A Fully Self-Aligned Amorphous Silicon Tft Technology for Large Area Image Sensors and Active-Matrix Displays

1998 ◽  
Vol 507 ◽  
Author(s):  
M J Powell ◽  
C Glasse ◽  
J E Curran ◽  
J R Hughes ◽  
I D French ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Amorphous Silicon ◽  
Doping Level ◽  
Field Effect ◽  
Channel Length ◽  
Image Sensors ◽  
Large Area ◽  
Active Matrix ◽  
New Process ◽  
Active Matrix Displays

ABSTRACTWe have developed a fully self-aligned amorphous silicon TFT technology, which is suitable for large area image sensors and active matrix displays. Self-alignment is achieved by defining the top nitride by back exposure and then forming source and drain contacts by ionimplantation and silicidation. We incorporate a low resistance gate metallisation process, by using Al metal, capped by Cr. We have compared the process of forming the silicide after the ion-implantation step, with a new process of forming the silicide first and then implanting through the formed silicide. We find a significant advantage to the latter method, where we can achieve a higher doping level and reduced contact resistance. We have therefore optimised our process based on this method. Transistor characteristics as a function of channel length for both methods show the improved contact resistance, obtained with the latter method. We obtain field effect mobilities of 0.7cm2V−1s−1, measured in the saturated region, for a channel length of 8μm.

Short Channel Amorphous Silicon MOS Structures with Reduced Capacitance

1985 ◽  
Vol 49 ◽  
Author(s):  
Z. Yaniv ◽  
V. Cannella ◽  
G. Hansell ◽  
M. Vijan
Keyword(s):  
Liquid Crystal ◽  
Amorphous Silicon ◽  
Liquid Crystal Displays ◽  
Channel Length ◽  
Oblique Angle Deposition ◽  
Large Area ◽  
Short Channel ◽  
Active Matrix ◽  
Silicon Alloy ◽  
Mos Structures

AbstractWe report improvements in device structures by the reduction of capacitance in short channel length thin film transistors of amorphous silicon alloy materials. Employing techniques similar to those previously reported [1,2], these MOS structures are fabricated with channel lengths of 1 to 2 micrometers using standard photolithography with 10 micrometer minimum feature size. Significant reductions in capacitance over earlier reported device designs were achieved by improvements in device geometry and innovative use of shadowing techniques utilizing oblique angle deposition to minimize overlap between electrodes. Theses reduced capacitance short channel length TFTs enhance the possibility of fabricating on-board drivers for active matrix liquid crystal displays using amorphous silicon alloy devices. Despite the relatively low mobility of amorphous silicon (∼ 1 cm2 /V-sec) these short channel length TFTs can provide currents large enough for operation in the megahertz regime when these reductions in capacitance are incorporated. The noncritical photolithography assures that devices may be fabricated over large area substrates (8" × 8") with acceptable yields. Computer simulations predict that these TFTs will be able to provide the necessary speed for on-substrate drivers. We will present experimental results from the new TFT structures and describe modeling methods and results for amorphous silicon TFT ring oscillators. We will discuss the significance of these results as they pertain to drive circuitry for large area liquid crystal displays.

A One-Micrometer Channel Length α-Si Thin-Film Field-Effect Transistor

1984 ◽  
Vol 33 ◽  
Author(s):  
Z. Yaniv ◽  
G. Hansell ◽  
M. Vijan ◽  
V. Cannella
Keyword(s):  
Thin Film ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Liquid Crystal Displays ◽  
Channel Length ◽  
Large Area ◽  
Short Channel ◽  
Threshold Voltages ◽  
Effect Transistor ◽  
Si Thin Film

ABSTRACTA new method of fabricating short channel α-Si TFTs has been developed. One-micrometer channel length α-Si thin-film field effect transistors have been fabricated and tested. Threshold voltages as low as 1.9V and field-effect mobilities as high as 1 cm 2/V-sec are reported. These devices were fabricated by techniques compatible with the production of large area liquid crystal displays.

Organic Thin-Film-Transistors with High on/off Ratios

1995 ◽  
Vol 377 ◽  
Author(s):  
L. Torsi ◽  
A. Dodabalapur ◽  
H. E. Katz ◽  
A. J. Lovinger ◽  
R. Ruel
Keyword(s):  
Thin Film ◽  
Thin Film Transistors ◽  
Switching Time ◽  
Channel Length ◽  
Organic Thin Film ◽  
Field Effect Mobility ◽  
Short Channel ◽  
Active Matrix ◽  
Current Voltage ◽  
Active Matrix Displays

ABSTRACTIn this article a new procedure to obtain alpha-hexathienylene (α-6T) thin-film-transistors (TFTs) with on/off ratios in excess of one million is reported. This procedure involves subjecting the TFTs to rapid thermal annealing. Previously, high on/off ratios have been achieved with improved device design and better chemical synthesis of α-6T oligomers. High on/off ratios, along with a switching time of ∼ 10 μs, render α-6T TFTs potential candidates as switching devices in active matrix displays. The experimental current-voltage (I-V) characteristics of oc-6T TFTs with channel length L = 4μm are also presented and a measured field effect mobility of 0.02 cm2/V-s is extracted from these characteristics using an analytical model which we have developed for short-channel α-6T TFTs.

Modeling and Characterization of the Hydrogenated Amorphous Silicon Metal Insulator Semiconductor Photosensors for Digital Radiography

2007 ◽  
Vol 989 ◽  
Author(s):  
Nader Safavian ◽  
Y. Vygranenko ◽  
J. Chang ◽  
Kyung Ho Kim ◽  
J. Lai ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Spectral Response ◽  
Large Area ◽  
Metal Insulator ◽  
Active Matrix ◽  
High Uniformity ◽  
Measurement Results ◽  
Temperature Deposition ◽  
Hydrogenated Amorphous

AbstractBecause of the inherent desired material and technological attributes such as low temperature deposition and high uniformity over large area, the amorphous silicon (a-Si:H) technology has been extended to digital X-ray diagnostic imaging applications. This paper reports on design, fabrication, and characterization of a MIS-type photosensor that is fully process-compatible with the active matrix a-Si:H TFT backplane. We discuss the device operating principles, along with measurement results of the transient dark current, linearity and spectral response.

Organic Materials for Large Area Electronics

2008 ◽  
Vol 608 ◽  
pp. 159-179 ◽  
Author(s):  
Richard Friend
Keyword(s):  
Thin Films ◽  
Field Effect ◽  
Organic Materials ◽  
Field Effect Transistors ◽  
Semiconductor Devices ◽  
Large Area ◽  
Active Matrix ◽  
Semiconductor Physics ◽  
Light Emitting ◽  
Wide Range

Organic materials have been developed to operate as the active semiconductor in a wide range of semiconductor devices, including light-emitting diodes, LEDs, field-effect transistors, FETs, and photovoltaic diodes, PVs. The ability to process these materials as thin films over large areas makes possible a range of applications, currently in displays, as LEDs and as active matrix FET arrays, and solar cells. This article reviews developments in semiconductor physics of these materials and in their application in semiconductor devices

Decoder-Type Gate Driver Circuits Fabricated with Amorphous Silicon Thin-Film Transistors for Active Matrix Displays

2011 ◽  
Vol 50 (3S) ◽  
pp. 03CC03 ◽  
Author(s):  
Tae-Wook Kim ◽  
Gyu-Tae Park ◽  
Byong-Deok Choi ◽  
MunPyo Hong ◽  
Jin-Nyoung Jang ◽  
...  
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Thin Film Transistors ◽  
Silicon Thin Film ◽  
Active Matrix ◽  
Active Matrix Displays ◽  
Gate Driver

Mechanisms of cross-talk in large area a-Si:H continuous image sensors

2001 ◽  
Vol 664 ◽  
Author(s):  
M. Mulato ◽  
J. P. Lu ◽  
S. E. Ready ◽  
K. Van Schuylenbergh ◽  
J. Ho ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Cross Talk ◽  
Field Enhancement ◽  
Image Sensors ◽  
Operating Conditions ◽  
Continuous Image ◽  
Large Area ◽  
Field Dependent ◽  
Image Blur ◽  
Interface Conduction

ABSTRACTWe report studies of the image-blur effects caused by lateral cross-talk between neighboring pixels of large-area amorphous silicon (a-Si:H) image sensors. The lateral conduction is attributed to three effects: conduction along the interface between the a-Si:H film and the underlying passivation; field-dependent electron injection at the edge of the sensor; and a field enhancement of the interface conduction due to the bias applied to the address lines. We show that the cross-talk can be controlled by choice of the operating conditions and optimization of the materials.

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