Comparison of Microstructure and Crystal Structure of Polycrystalline Silicon Exhibiting Varied Textures Fabricated by Microwave and Very High Frequency Plasma Enhanced Chemical Vapor Deposition and Their Transport Properties

Abstract

The complexity of a system, in general, makes it difficult to determine some or almost all matrix elements of its operators. The lack of accuracy acts as a source of randomness for the matrix elements which are also subjected to an external potential due to existing system conditions. The fluctuation of accuracy due to varying system conditions leads to a diffusion of the matrix elements. We show that, for single-well potentials, the diffusion can be described by a common mathematical formulation where system information enters through a single parameter. This further leads to a characterization of physical properties by an infinite range of single-parametric universality classes.

Growth, structure, and transport properties of thin (>10 nm) n-type microcrystalline silicon prepared on silicon oxide and its application to single-electron transistor

“…As Kamiya et al report, the growth of the ͑400͒ oriented poly-Si depends significantly on the growth surface structure. 13,38 Under conditions where ͑220͒ oriented poly-Si films are grown, the grain height tends to decrease with an increasing hydrogen mixing ratio, which is similar to the result obtained with a SiH 4 /H 2 system. 39 In low-temperature PECVD system using H 2 and SiH 4 gases, the majority of the growth surface is covered with hydrogen under high hydrogen mixing ratio conditions.…”

“…We have reported a similar discrepancy between scanning electron microscopy ͑SEM͒ observation and XRD analysis for ͑220͒ oriented poly-Si. 13 This is because the large grains observed by SEM consist of smaller single-domain crystallites which are observed by XRD: i.e., the larger grains have small secondary structures. Similarly, it is thought that the Raman analysis provides grain sizes of the smaller singledomain crystallites and that the c-Si:H contains small grains with size of ϳ3 nm independent of film thickness, suggesting that new nuclei are formed at/near the growth surface during the film deposition.…”

“…[7][8][9][10] In our previous work, we have reported on high crystallinity, high quality poly-Si:H films prepared on glass from SiF 4 and H 2 gas mixtures, where a fluorinated source gas enhances crystallization and crystallite growth. 11 The film microstructures including the grain orientation are controlled by selecting appropriate deposition conditions, 12,13 which would lead to suitable device applications. For example, ͑220͒ oriented poly-Si can be grown at small gas flow ratios ͑e.g., SiF 4 /H 2 Ͻ30/10 sccm͒ at 300°C.…”

“…14,15 The ͑400͒ oriented poly-Si can be grown at a higher gas flow ratio of 60/3 sccm at 300°C and it has a smoother surface, higher quality crystalline grains and a larger carrier mobility. 13 This material may be used for high performance TFT. 5 It is also possible to grow c-Si:H with high crystallinity ͑crystal fraction Ͼ60%͒ at temperatures as low as 50°C with small SiF 4 /H 2 a͒ Electronic mail: kamiya@iem.titech.ac.jp ratios.…”

Carrier Transport in Ultra-Thin Nano/Polycrystalline Silicon Films and Nanowires

“…It indicates that each crystalline grain ("K" and "L" in the figure) is spherical and smaller than the large corn-shaped structure. This type of secondary microstructure feature is often observed in µc-Si:H [8,9]. From high resolution TEM, we confirmed that the smaller structures corresponded to single-domain crystalline silicon grains 4 nm -8 nm in size.…”