Growth and Properties of Tetrahedrally-Bonded Thin-Film Amorphous Silicon Alloys

ABSTRACTThere is a rapid growth of interest in the application of amorphous silicon alloy thin film devices to large area microelectronic circuits. Increased current levels are a constant goal since gains in device current result in proportional gains in power and speed. Mobility limitations in amorphous silicon thin film transistors have directed interest toward short conduction channel devices to achieve higher current levels; furthermore, compatibility with large area processing makes photolithography with 10μm feature size very attractive. Consequently, innovative techniques, which define channel lengths by processing parameters rather than by mask feature size are necessary. Previous work has applied such techniques to vertical structure TFT's which define channel lengths by the vertical height of deposited layers. Here, we report on a technique which achieves short channel lengths in planar structures using etching parameters to define short channel lengths. Amorphous silicon alloy TFTs have been fabricated with channel lengths of ≈2μm which reach currents of lma. These techniques broaden the range of application of amorphous silicon alloy TFTs by providing devices capable of operating at higher currents and higher speeds.

Download Full-text

The Instability Characteristics of Amorphous Silicon Thin Film Transistors with Various Interfacial and Bulk Defect States

Japanese Journal of Applied Physics ◽

10.1143/jjap.36.6226 ◽

1997 ◽

Vol 36 (Part 1, No. 10) ◽

pp. 6226-6229 ◽

Cited By ~ 1

Author(s):

Huang-Chung Cheng ◽

Jun-Wei Tsai ◽

Chun-Yao Huang ◽

Fang-Chen Luo ◽

Hsing-Chien Tuan

Keyword(s):

Thin Film ◽

Amorphous Silicon ◽

Thin Film Transistors ◽

Defect States ◽

Silicon Thin Film

Download Full-text

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

10.1117/12.389409 ◽

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

Download Full-text

Hot-Wire Deposited Amorphous Silicon Thin-Film Transistors

MRS Proceedings ◽

10.1557/proc-424-31 ◽

1996 ◽

Vol 424 ◽

Cited By ~ 1

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.

Download Full-text

Development of n-μc-SiOx:H as cost effective back reflector and its application to thin film amorphous silicon solar cells

Solar Energy ◽

10.1016/j.solener.2013.09.021 ◽

2013 ◽

Vol 97 ◽

pp. 591-595 ◽

Cited By ~ 12

Author(s):

C. Banerjee ◽

T. Srikanth ◽

U. Basavaraju ◽

R.M. Tomy ◽

M.G. Sreenivasan ◽

...

Keyword(s):

Thin Film ◽

Solar Cells ◽

Amorphous Silicon ◽

Cost Effective ◽

Silicon Solar Cells ◽

Back Reflector

Download Full-text

Hydrogenated Nanocrystalline Silicon Thin Film Transistor Array for X-ray Detector Application

MRS Proceedings ◽

10.1557/proc-1066-a16-07 ◽

2008 ◽

Vol 1066 ◽

Author(s):

Kyung-Wook Shin ◽

Mohammad R. Esmaeili-Rad ◽

Andrei Sazonov ◽

Arokia Nathan

Keyword(s):

Thin Film ◽

Amorphous Silicon ◽

Threshold Voltage ◽

Hydrogenated Amorphous Silicon ◽

Nanocrystalline Silicon ◽

Amorphous Selenium ◽

Breakdown Field ◽

Storage Capacitor ◽

X Ray ◽

Hydrogenated Amorphous

ABSTRACTHydrogenated nanocrystalline silicon (nc-Si:H) has strong potential to replace the hydrogenated amorphous silicon (a-Si:H) in thin film transistors (TFTs) due to its compatibility with the current industrial a-Si:H processes, and its better threshold voltage stability [1]. In this paper, we present an experimental TFT array backplane for direct conversion X-ray detector, using inverted staggered bottom gate nc-Si:H TFT as switching element. The TFTs employed a nc-Si:H/a-Si:H bilayer as the channel layer and hydrogenated amorphous silicon nitride (a-SiNx) as the gate dielectric; both layers deposited by plasma enhanced chemical vapor deposition (PECVD) at 280°C. Each pixel consists of a switching TFT, a charge storage capacitor (Cpx), and a mushroom electrode which serves as the bottom contact for X-ray detector such as amorphous selenium photoconductor. The chemical composition of the a-SiNx was studied by Fourier transform infrared spectroscopy. Current-voltage measurements of the a-SiNx film demonstrate that a breakdown field of 4.3 MV/cm.. TFTs in the array exhibits a field effect mobility (μEF) of 0.15 cm2/V·s, a threshold voltage (VTh) of 5.71 V, and a subthreshold leakage current (Isub) of 10−10 A. The fabrication sequence and TFT characteristics will be discussed in details.

Download Full-text