Elimination of Subboundaries from Zone-Melting-Recrystallized Silicon-On-Insulator Films

1985 ◽  
Vol 53 ◽  
Author(s):  
M. W. Geis ◽  
C. K. Chen ◽  
Henry I. Smith ◽  
P. M. Nitishin ◽  
B-Y. Tsaur ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Thermal Gradient ◽  
Zone Melting ◽  
Silicon On Insulator ◽  
Crystalline Defects ◽  
Si Films

ABSTRACTSince the introduction of zone-melting recrystallization (ZMR)for silicon-on-insulator (SOI) films, subboundaries (low-angle grain boundaries) have been the major crystalline defects in recrystallized films. By using an improved ZMR procedure, subboundaries have been eliminated over large areas. The improvements include the use of 1-µm-thick polycrystalline-Si films deposited on 2-µm-thick thermal SiO2 film (instead of 0.5-µm-thick Si and SiO2 films), a new encapsulation technique, and improved control of the thermal gradient during ZMR. Recrystallized SOI films without subboundaries contain isolated dislocations with densities <2 × 106 cm−2.

Melting and Solidification Dynamics in Zone Melting of Si Films.

1987 ◽  
Vol 107 ◽  
Author(s):  
D. Dutartre
Keyword(s):  
Thin Films ◽  
Surface Morphology ◽  
Zone Melting ◽  
Silicon On Insulator ◽  
Experimental Conditions ◽  
Melting Front ◽  
Physical Mechanisms ◽  
Si Films ◽  
Melting And Solidification

AbstractWe discuss the physics involved in the melting and solidification of Silicon On Insulator thin films (SOI) using lamp or graphite strip heaters. The melting front, called “explosive melting”, controls to a large part the final morphological quality of the SOI film. It exhibits instabilities which can (i) nucleate the dewetting of the film, (ii) cause voids, and (iii) produce a poor surface morphology. The morphologies of the solidification fronts are analyzed. We show that, depending on the experimental conditions, different physical mechanisms are responsible for the front breakdown. Thus we propose that the variety of front morphologies results from the variety of the mechanisms involved, and of their combinations with the “faceting effects”.

Silicon-On-Insulator Mosfets Fabricated in Zone-Melting-Recrystallized Poly-Si Films on SiO2

1981 ◽  
Vol 4 ◽  
Author(s):  
B­Y. Tsaur ◽  
M. W. Gels ◽  
John C. C. Fan ◽  
D. J. Silversmith ◽  
R. W. Mountain
Keyword(s):  
Carrier Mobility ◽  
High Surface ◽  
Zone Melting ◽  
Silicon On Insulator ◽  
Surface Electron ◽  
Leakage Currents ◽  
Si Substrates ◽  
Enhancement Mode ◽  
Low Leakage ◽  
Si Films

ABSTRACTN- and p-channel enhancement-mode MOSFETs have been fabricated in Si films prepared by zone-melting recrystallization of poly-Si deposited on SiO2-coated Si substrates. The transistors exhibit high surface mobilities, in the range of 560–620 cm2/V−s for electrons and 200–240 cm2/V−s for holes, and low leakage currents of the order of 0.1 pA/μm (channel width). Uniform device performance with a yield exceeding 90% has been measured in tests of more than 100 devices. The interface between the Si film and the SiO2 layer on the substrate is characterized by an oxide charge density of 1–2 × 1011 cm−2 and a high surface carrier mobility. N-channel MOSFETs fabricated inSi films recrystallized on SiO2-coated fused quartz subtrates exhibit surface electron mobilities substantially higher than those of single-crystal Si devices because the films are under a large tensile stress.

Thermal Stress During Zone-Melting-Recrystallization of Silicon on Insulator Films: The Origin of Subboundaries and In-Plane Orientation of SOI

1985 ◽  
Vol 53 ◽  
Author(s):  
J.M. Gibson ◽  
L.N. Pfeiffer ◽  
K.W. West ◽  
D.C. Joy
Keyword(s):  
Thermal Stress ◽  
Grain Boundaries ◽  
Tilt Angle ◽  
Elastic Anisotropy ◽  
Zone Melting ◽  
Silicon On Insulator ◽  
Experimental Results ◽  
Plane Orientation

ABSTRACTThe effect of thermal stress during zone-melting recrystallization of silicon on insulator films is considered. New experimental results from graphite-strip heated films are drawn upon. It is found that low-angle grain boundaries exhibit an inverse dependence between spacing and tilt angle. This is explained semiquantitatively by a model in which thermal stress induced film buckling is responsible for the existence of low-angle grain boundaries. It is also suggested that the predominance of the <100> orientation in these films is partly due to thermal stress and the elastic anisotropy of silicon. Thus thermal stress is proposed as the origin of the two major features of zone-melted films.

Capping Techniques for Zone-Melting-Recrystallized Si-On-Insulator Films

1985 ◽  
Vol 53 ◽  
Author(s):  
C.K. Chen ◽  
L. Pfeiffer ◽  
K.W. West ◽  
M.W. Gels ◽  
S. Darack ◽  
...  
Keyword(s):  
Crystallographic Texture ◽  
Auger Spectroscopy ◽  
Zone Melting ◽  
Silicon On Insulator ◽  
Capping Layer ◽  
Spectroscopy Studies ◽  
Si Films ◽  
Film Annealing

ABSTRACTTo prepare silicon-on-insulator (SOI) films by graphite-strip-heater zone-melting recrystallization (ZMR), a capping technique must be used to insure wetting by the molten Si zone. We have demonstrated two new capping techniques that result in reproducible wetting without degrading the crystallographic texture of the recrystallized film: annealing SiO2- capped Si films in NH3 and depositing two SiNx layers with carefully controlled compositions on the SiO2 capping layer. Wetting is promoted by the incorporation of trace amounts of nitrogen at the Si-SiO2 interface. Both N implantation experiments and Auger spectroscopy studies establish that the presence of less than a monolayer of nitrogen at this interface is sufficient to insure wetting.

Crystalline Films on Amorphous Substrates by Zone Melting and Surface-Energy-Driven Grain Growth in Conjunction with Patferning

1985 ◽  
Vol 53 ◽  
Author(s):  
Henry I. Smith ◽  
M. W. Geis ◽  
C. V. Thompson ◽  
C. K. Chen
Keyword(s):  
Low Temperature ◽  
Surface Energy ◽  
Grain Boundaries ◽  
Grain Growth ◽  
High Temperatures ◽  
Zone Melting ◽  
Si Substrates ◽  
Crystalline Films ◽  
Amorphous Substrates ◽  
Si Films

ABSTRACTTwo approaches to preparing oriented crystalline films on amorphous substrates are reviewed briefly: zone-melting recrystallization (ZMR) and surface-energy-driven grain growth (SEDGG). In both approaches patterning can be employed either to establish orientation or to control the location of defects. ZMR has been highly successful for the growth of Si films on oxidized Si substrates, but its applicability is limited by the high temperatures required. SEDGG has been investigated as a potentially universal, low temperature approach. It has been demonstrated in Si, Ge, and Au. Surface gratings favor the growth of grains with a specific in-plane orientation. In order for SEDGG to be of broad practical value, the mobility of semiconductor grain boundaries must be increased substantially. Mobility enhancement has been achieved via doping and ion bombardment.

Characterization & Analysis of Sub-Grain Boundaries in Sequential Lateral Solidification Processed SOI Films

2001 ◽  
Vol 685 ◽  
Author(s):  
M. A. Crowder ◽  
A. B. Limanov ◽  
B. A. Turk ◽  
James S. Im
Keyword(s):  
Plastic Deformation ◽  
Grain Boundaries ◽  
Silicon On Insulator ◽  
Deformation Model ◽  
Directionally Solidified ◽  
Projection System ◽  
Transitional Area ◽  
Sequential Lateral Solidification ◽  
Si Films ◽  
Free Area

AbstractThe nature of the formation of sub-grain boundaries within sequential lateral solidification (SLS) processed thin silicon films has been examined using single crystal Si films as a pre- cursor material. Experimental details include the use of an excimer laser projection system and straight-slit beamlets to produce directionally solidified microstructures. Within the SLS processed silicon-on-insulator (SOI) films, three microstructurally distinct regions are identi-fied: (1) an initial planar defect-free area (the extent of which can depend on laser fluence and orientation); (2) a transitional area within which the sub-grain boundaries appear and propagate in a well-defined direction relative to the crystallographic orientation; and (3) a final area characterized by sub-grain boundaries aligning approximately to the scan direction, and the in-plane texture becoming more random. We discuss the results within the context of a plastic deformation model of sub-grain boundary formation.

Sub-Boundary Formation and Suppression in Silicon films Recrystallized by Scanned Zone Melting

1983 ◽  
Vol 25 ◽  
Author(s):  
Loren Pfeiffer ◽  
J. M. Gibson ◽  
T. Kovacs
Keyword(s):  
Grain Boundaries ◽  
Zone Melting ◽  
Silicon Films ◽  
Boundary Formation ◽  
Buried Oxide ◽  
Si Films

ABSTRACTWe observe that the formation of low angle grain boundaries (sub-boundaries) depends strongly on the thickness of the recrystallized Si film. The average lateral spacing between adjacent sub-boundaries increases from 40 μm for 4000Å films to 500 μm for unseeded Si films 30 μm thick. For seeded 30 μm Si films on 1.6 mm by 1.6 mm buried oxide islands, areas exceeding 1.0 mm by 1.0 mm have been recrystallized which are free of all sub-boundaries, but which contain dislocations in other configurations.

Characterization, Control, and Reduction of Subboundaries in Silicon on Insulators

1984 ◽  
Vol 35 ◽  
Author(s):  
M. W. Geis ◽  
C. K. Chen ◽  
Henry I. Smith ◽  
R. W. Mountain ◽  
C. L. Doherty
Keyword(s):  
Defect Structure ◽  
Chemical Etching ◽  
Zone Melting ◽  
Constitutional Supercooling ◽  
Cellular Growth ◽  
Semiconductor Films ◽  
Crystalline Defects ◽  
Transmission Electron ◽  
Thin Semiconductor ◽  
Si Films

ABSTRACTSubboundaries are the major crystalline defects in thin semiconductor films produced by zone-melting recrystallization (ZMR). Using transmission electron microscopy (TEM) and chemical etching we have analyzed the angular discontinuity and defect structure of subboundaries in ZMR Si films. Annealing in oxygen has resulted in the elimination of dislocation bands from sizable regions of some films. Calculations suggest that cellular growth due to constitutional supercooling may not occur in some Si ZMR.

Microscopy of Thin Si Films During Lamp Zone Melting

1985 ◽  
Vol 53 ◽  
Author(s):  
D. Dutartre ◽  
M. Haond ◽  
D. Bensahel
Keyword(s):  
Zone Melting ◽  
Silicon On Insulator ◽  
Spatial Modulation ◽  
Freezing Front ◽  
Melting Front ◽  
Scan Speed ◽  
Entrainment Effect ◽  
Si Films ◽  
Melting And Solidification

ABSTRACTThe melting and solidification fronts of thin Silicon On Insulator (SOI) films have been observed in-situ. The melting front does not advance continuously but by bursts. This so called “explosive melting” allows to explain the appearance of defects (such as voids and surface roughness) observed in the recrystallized film. The freezing front is observed in the case where a pattern for the entrainment of the defects has been etched in the underlying oxide: we show that the entrainment effect is due to the spatial modulation of the solidification front by the structure. Furthermore, the scan speed influences the morphology of the liquid/solid interface and the defect entrainment efficiency.

High-Voltage Electron Microscopy Investigation of Subgrain Boundaries in Recrystallized Silicon-On-Insulator Structures

1984 ◽  
Vol 35 ◽  
Author(s):  
H. Baumgart ◽  
F. Phillipp
Keyword(s):  
Electron Microscopy ◽  
High Voltage ◽  
Zone Melting ◽  
Silicon On Insulator ◽  
Stress Concentrations ◽  
Growth Interface ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
High Voltage Electron ◽  
Si Films

ABSTRACTThe microstructure of high-quality recrystallized Si films on SiO2 substrates produced by CO2 laser induced zone-melting has been investigated by high voltage electron microscopy (HVEM). Subgrain boundaries represent the major defects in these recrystallized films. The origin of the subboundaries has been traced to periodic internal stress concentrations occurring at the faceted growth interface. These highly localized stresses cause plastic deformation of the growing single crystal film by nucleation of an array of slip dislocations. The mechanism responsible for the formation of subgrain boundaries has been revealed to be polygonization, where thermally activated dislocations rearrange themselves into the lower energy configuration of the low angle grain boundary.

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