Poly-crystalline silicon with columnar structure

Author(s):  
Bernhard Authier
1989 ◽  
Vol 149 ◽  
Author(s):  
Scott J. Jones ◽  
Susanne M. Lee ◽  
Warren A. Turner ◽  
William Paul

ABSTRACTA series of glow discharge a-Ge:H films has been produced at substrate temperatures, Ts, between 100 and 350°C. The films were structurally characterized using Differential Scanning Calorimetry (DSC), Gas Evolution (GE), Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). The DSC and GE results are substrate dependent. Two exothermic peaks are seen in DSC spectra for films deposited on aluminum foil while only one peak, identified by Raman measurements as the crystallization peak, is seen for samples deposited on beryllium, NaCl, carbon coated mica, crystalline silicon and 7059 glass. The crystallization peak temperature of films deposited on 7059 glass decreases with increasing Ts until 250°C where it then remains constant up to Ts=350°C. GE results show a relative increase of high temperature evolution with an increase in Ts. A well defined island/tissue structure seen in TEM micrographs of low Ts films disappears at higher Ts values. SEM measurements show columnar structure present only in films produced at Ts≤250°C. All the structural measurements point to a more stable material of higher density for Ts>250°C.


1998 ◽  
Vol 13 (10) ◽  
pp. 2721-2731 ◽  
Author(s):  
J. C. Muller ◽  
S. Martinuzzi

For photovoltaic applications silicon is still the predominant material. Besides monocrystalline Czochralski wafers (Cz-Si), multicrystalline sheets (mc-Si) play an important role in terrestrial power applications (almost 50%). Large mc-Si ingots (up to 250 kg) are now produced in large scale by the industry using various directional solidification methods in appropriate crucibles (or molds). However, if the crystallographic properties are now quite satisfactory (columnar structure with large grains of more than 1 cm2, dislocations and intragrains defects), multicrystalline silicon contains larger quantities of impurities than single crystalline silicon which can have detrimental effects on the bulk minority carrier diffusion length (Ln,p). These impurities, including metals as well as high concentrations of carbon and/or oxygen, can degrade the photovoltaic properties of solar cells. Thermal treatments such as gettering, performed in a classical or rapid thermal furnace, studied separately or in conjunction with the doping steps can limit or avoid the degradation of the bulk diffusion length, but its efficiency is strongly dependent on the presence of these impurities in Si.


2013 ◽  
Vol 58 (2) ◽  
pp. 142-150 ◽  
Author(s):  
A.V. Sachenko ◽  
◽  
V.P. Kostylev ◽  
V.G. Litovchenko ◽  
V.G. Popov ◽  
...  

2020 ◽  
Vol 65 (3) ◽  
pp. 236
Author(s):  
R. M. Rudenko ◽  
O. O. Voitsihovska ◽  
V. V. Voitovych ◽  
M. M. Kras’ko ◽  
A. G. Kolosyuk ◽  
...  

The process of crystalline silicon phase formation in tin-doped amorphous silicon (a-SiSn) films has been studied. The inclusions of metallic tin are shown to play a key role in the crystallization of researched a-SiSn specimens with Sn contents of 1–10 at% at temperatures of 300–500 ∘C. The crystallization process can conditionally be divided into two stages. At the first stage, the formation of metallic tin inclusions occurs in the bulk of as-precipitated films owing to the diffusion of tin atoms in the amorphous silicon matrix. At the second stage, the formation of the nanocrystalline phase of silicon occurs as a result of the motion of silicon atoms from the amorphous phase to the crystalline one through the formed metallic tin inclusions. The presence of the latter ensures the formation of silicon crystallites at a much lower temperature than the solid-phase recrystallization temperature (about 750 ∘C). A possibility for a relation to exist between the sizes of growing silicon nanocrystallites and metallic tin inclusions favoring the formation of nanocrystallites has been analyzed.


Author(s):  
Yuk L. Tsang ◽  
Alex VanVianen ◽  
Xiang D. Wang ◽  
N. David Theodore

Abstract In this paper, we report a device model that has successfully described the characteristics of an anomalous CMOS NFET and led to the identification of a non-visual defect. The model was based on detailed electrical characterization of a transistor exhibiting a threshold voltage (Vt) of about 120mv lower than normal and also exhibiting source to drain leakage. Using a simple graphical simulation, we predicted that the anomalous device was a transistor in parallel with a resistor. It was proposed that the resistor was due to a counter doping defect. This was confirmed using Scanning Capacitance Microscopy (SCM). The dopant defect was shown by TEM imaging to be caused by a crystalline silicon dislocation.


Sign in / Sign up

Export Citation Format

Share Document