Rapid solid-phase crystallization of high-rate, hot-wire chemical-vapor-deposited hydrogenated amorphous silicon

2006 ◽  
Vol 89 (16) ◽  
pp. 161910 ◽  
Author(s):  
David L. Young ◽  
Paul Stradins ◽  
Yueqin Xu ◽  
Lynn Gedvilas ◽  
Bob Reedy ◽  
...  
2005 ◽  
Vol 862 ◽  
Author(s):  
David L. Young ◽  
Paul Stradins ◽  
Eugene Iwaniczko ◽  
Bobby To ◽  
Bob Reedy ◽  
...  

AbstractWe measure times for complete solid phase crystallization (SPC) of hydrogenated amorphous silicon (a-Si:H) thin films that vary eight orders of magnitude, from a few ms to a few days. The time-to-crystallization activation energy is consistent with literature values of approximately 3.4 eV but the prefactor is markedly different for hot-wire chemical vapor deposition (HWCVD) films than for plasma-enhanced (PE) CVD films. The crystallized films were 0.3 – 2 μm thick, and deposited by high deposition rate (10-100 Å/s) HWCVD or standard PECVD onto glass substrates. We annealed these a-Si:H films over a wide temperature range (500 to 1100 °C) using techniques including simple hot-plates and tube furnaces, rapid thermal annealing by a tungsten-halogen lamp, and microwave electromagnetic heating at 2.45 GHz (magnetron) and 110 GHz (gyrotron).


1998 ◽  
Vol 507 ◽  
Author(s):  
Xiao. Liu ◽  
E. Iwaniczko ◽  
R.O. Pohl ◽  
R.S. Crandall

ABSTRACTWe have studied the elastic properties of hydrogenated amorphous silicon (a-Si:H) prepared by hot wire chemical-vapor deposition (HWCVD). With 1 at.% H, this material has been found to be the only amorphous solid which has a low-temperature internal friction more than two orders of magnitude smaller than all other amorphous solids studied to date, as reported recently. As the hydrogen concentration increases above 1 at.%, a broad relaxation peak in internal friction around 5 K is observed. Even more striking is an extremely narrow peak in internal friction accompanied by a discontinuous change in the sound velocity at 13.8 K, which coincides with the triple point temperature of molecular hydrogen. Evidences are provided to show that this anomaly is caused by bulk molecular hydrogen which undergoes a liquid-solid phase transition. This is the first observation for the existence of bulk H2 in HWCVD a-Si:H.


2003 ◽  
Vol 762 ◽  
Author(s):  
Guofu Hou ◽  
Xinhua Geng ◽  
Xiaodan Zhang ◽  
Ying Zhao ◽  
Junming Xue ◽  
...  

AbstractHigh rate deposition of high quality and stable hydrogenated amorphous silicon (a-Si:H) films were performed near the threshold of amorphous to microcrystalline phase transition using a very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) method. The effect of hydrogen dilution on optic-electronic and structural properties of these films was investigated by Fourier-transform infrared (FTIR) spectroscopy, Raman scattering and constant photocurrent method (CPM). Experiment showed that although the phase transition was much influenced by hydrogen dilution, it also strongly depended on substrate temperature, working pressure and plasma power. With optimized condition high quality and high stable a-Si:H films, which exhibit σph/σd of 4.4×106 and deposition rate of 28.8Å/s, have been obtained.


1999 ◽  
Vol 557 ◽  
Author(s):  
Xiao Liu ◽  
R.O. Pohl ◽  
R.S. Crandall

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.


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