Elastic Properties of Several Silicon Nitride Films

2007 ◽  
Vol 989 ◽  
Author(s):  
Xiao Liu ◽  
Thomas H Metcalf ◽  
Qi Wang ◽  
Douglas M Photiadis
Keyword(s):  
Chemical Vapor Deposition ◽  
Silicon Nitride ◽  
Internal Friction ◽  
Amorphous Silicon ◽  
Elastic Properties ◽  
Vapor Deposition ◽  
Film Growth ◽  
Chemical Vapor ◽  
Structural Disorder ◽  
Order Of Magnitude

AbstractWe have measured the internal friction (Q-1) of amorphous silicon nitride (a-Si3Nx) films prepared by a variety of methods, including low-pressure chemical-vapor deposition (LPCVD), plasma-enhanced chemical-vapor deposition (PECVD), and hot-wire chemical-vapor deposition (HWCVD) from 0.5 K to room temperature. The measurements are made by depositing the films onto extremely high-Q silicon double paddle oscillator substrates with a resonant frequency of ~5500 Hz. We find the elastic properties of these a-Si3N4 films resemble those of amorphous silicon (a-Si), demonstrating considerable variation, depending on the film growth methods and post deposition annealing. The internal friction for most of the films shows a broad temperature-independent plateau below 30 K, characteristic of amorphous solids. The values of Q-1, however, vary from film to film in this plateau region by more than one order of magnitude. This is typical for tetrehedrally bonded amorphous thin films, like a-Si, a-Ge, and a-C. The PECVD films have the highest Q-1 just like an ordinary amorphous solid, while LPCVD films have an internal friction more than one order of magnitude lower. All the films show a reduction of Q-1 after annealing at 800°C, even for the LPCVD films which were prepared at 850°C. This can be viewed as a reduction of structural disorder.

Low Temperature Tungsten, Tungsten Carbide and Tantalum Carbide Film Growth

2000 ◽  
Vol 648 ◽  
Author(s):  
Y.-M. Sun ◽  
S.Y. Lee ◽  
E. R. Engbrecht ◽  
K. Pfeifer ◽  
S. Smith ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Chemical Vapor Deposition ◽  
Tungsten Carbide ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
Film Growth ◽  
Chemical Vapor ◽  
Tantalum Carbide ◽  
Microscopy Imaging ◽  
Order Of Magnitude

Abstract:Low temperature chemical vapor deposition of tungsten, tungsten carbide and tantalum carbide films on SiO2/Si(100) surfaces was studied by X-ray photoelectron spectroscopy (XPS) and electron microscopy. Tungsten carbide films were deposited using the W(CO)6precursor with and without ethylene over temperatures ranging from 250 to 500 °C. The films grown without ethylene contained approximately 13 % carbon and 6 % oxygen. Cross section scanning electron microscopy imaging of the films grown at various temperatures without ethylene shows a polycrystalline microstructure, and the grain size increases dramatically as the growth temperature increases. Introducing ethylene increased carbon incorporation and changed the microstructure to amorphous-like. The tungsten to carbon ratio was approximately 2 at growth below 500 °C, and reached ~ 1.2 above 500 °C. The tantalum carbide films were deposited in a plasma enhanced chemical vapor deposition (PECVD) process using methane. The PECVD tantalum carbide films were conductive with a resistivity of ~1000 µΩ cm, which is about one order of magnitude lower than thermally grown films from pentakisdimethylamino tantalum.

Thin-Film Transistors based on Hot-Wire Amorphous Silicon on Silicon Nitride

1999 ◽  
Vol 557 ◽  
Author(s):  
B. Stannowski ◽  
H. Meiling ◽  
A. M. Brockhoff ◽  
R. E. I. Schropp
Keyword(s):  
Thin Film ◽  
Chemical Vapor Deposition ◽  
Silicon Nitride ◽  
Glow Discharge ◽  
Silicon Dioxide ◽  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Thin Film Transistors ◽  
Chemical Vapor ◽  
Hot Wire

AbstractWe present state-of-the-art thin-film transistors (TFTs) incorporating amorphous silicon i-layers deposited by hot-wire chemical vapor deposition. The TFTs are deposited on glow-discharge silicon nitride as well as on thermally-grown silicon dioxide. The devices on silicon nitride have a field-effect mobility above 0.7 cm2/Vs, a threshold voltage around 2 V and a sub-threshold slope as low as 0.5 V/dec. As commonly observed, the TFTs on silicon-dioxide have higher values for the threshold voltage and the sub-threshold slope. In the annealed state the hot-wire TFTs show almost the same properties as TFTs deposited by conventional plasma-enhanced chemical vapor deposition. Nevertheless, the stress-time dependent behavior under prolonged gate-voltage stress at elevated temperature is different from that of the glow-discharge devices. The hot-wire TFTs are clearly more stable than their glow-discharge counterparts. Furthermore, we found differences in the stress behavior of the hot-wire TFTs deposited on silicon nitride and silicon dioxide.

Light-Induced Increase in Two-Level Tunneling States in Hydrogenated Amorphous Silicon

1999 ◽  
Vol 557 ◽  
Author(s):  
Xiao Liu ◽  
R.O. Pohl ◽  
R.S. Crandall
Keyword(s):  
Chemical Vapor Deposition ◽  
Low Temperature ◽  
Internal Friction ◽  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Room Temperature ◽  
Hydrogenated Amorphous Silicon ◽  
Chemical Vapor ◽  
Hot Wire ◽  
Hydrogenated Amorphous

AbstractWe observe an increase of the low-temperature internal friction of hydrogenated amorphous silicon prepared by both hot-wire and plasma-enhanced chemical-vapor deposition after extended light-soaking at room temperature. This increase, and the associated change in sound velocity, can be explained by an increase of the density of two-level tunneling states, which serves as a measure of the lattice disorder. The amount of increase in internal friction is remarkably similar in both types of films although the amount and the microstructure of hydrogen are very different. Experiments conducted on a sample prepared by hot-wire chemical-vapor deposition show that this change anneals out gradually at room temperature in about 70 days. Possible relation of the light-induced changes in the low-temperature elastic properties to the Staebler-Wronski effect is discussed.

Towards an All-Hot-Wire TFT: Silicon Nitride and amorphous Silicon deposited by Hot-Wire Chemical Vapor Deposition

2001 ◽  
Vol 664 ◽  
Author(s):  
B. Stannowski ◽  
M.K. van Veen ◽  
R.E.I. Schropp
Keyword(s):  
Thin Film ◽  
Chemical Vapor Deposition ◽  
Silicon Nitride ◽  
Electrical Properties ◽  
Substrate Temperature ◽  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Thin Film Transistors ◽  
Chemical Vapor ◽  
Hot Wire

ABSTRACTWe present thin-film transistors with both amorphous silicon and silicon nitride deposited by hot-wire chemical vapor deposition. Hot-wire amorphous silicon with good electrical properties was deposited from the decomposition of silane at a substrate temperature of 250°C. For Hot-wire silicon nitride we used silane and ammonia at a substrate temperature of 340°C. In this paper we address structural and electrical properties of this material. A high ammonia flow results in porous films that exhibit post-deposition oxidation. By limiting the ammonia/silane ratio to 30, compact layers with a hydrogen content of only 10 at.% and a refractive index of 1.95 are obtained. Using this layer as gate dielectric results in thin-film transistors with good switching behavior and a field-effect mobility of 0.3 cm2/Vs.

Low Temperature Vibrational Properties of Amorphous Silicon

1998 ◽  
Vol 507 ◽  
Author(s):  
R. S. Crandall ◽  
E. Iwaniczko ◽  
A. H. Mahan ◽  
X. Liu ◽  
R.O. Pohl
Keyword(s):  
Chemical Vapor Deposition ◽  
Low Temperature ◽  
Internal Friction ◽  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Amorphous Solids ◽  
Vibrational Properties ◽  
Deposition Method ◽  
Hot Wire

ABSTRACTWe present internal friction and shear modulus measurements of amorphous silicon (a-Si) and germanium (a-Ge) films. The temperature independent plateau in internal friction below 10 K, common to all amorphous solids, also exists in these films. However, its magnitude which depends critically on the deposition method is smaller than found for all other amorphous solids. In particular, hydrogenated a-Si with about 1 at. % H prepared by hot-wire chemical-vapor-deposition leads to an internal friction nearly three orders of magnitude smaller than observed for all other amorphous solids. The internal friction increases after the hydrogen is removed by effusion.

Amorphous silicon nitride deposited by hot-wire chemical vapor deposition

2004 ◽  
Vol 96 (5) ◽  
pp. 2973-2979 ◽  
Author(s):  
Fengzhen Liu ◽  
Scott Ward ◽  
Lynn Gedvilas ◽  
Brian Keyes ◽  
Bob To ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Hot Wire ◽  
Amorphous Silicon Nitride
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