Sublimation Sandwich Growth of Free Standing GaN Crystals

1997 ◽  
Vol 482 ◽  
Author(s):  
Yu. A. Vodakov ◽  
E. N. Mokhov ◽  
M. G. Ramm ◽  
M. S. Ramm ◽  
A. D. Roenkov ◽  
...  
Keyword(s):  
Growth Rates ◽  
Epitaxial Layers ◽  
Free Standing ◽  
Sandwich Method

AbstractThick epitaxial layers of GaN on SiC and sapphire are grown by using the sublimation sandwich method. It is shown that growth of good quality GaN crystals with the growth rates up to 0.5 mm/hour is possible using this technique. The grown layers have been separated from the seed and free standing GaN crystals up to 15 mm size were obtained.

Very High Growth Rate of 4H-SiC Using MTS as Chloride-Based Precursor

2008 ◽  
Vol 600-603 ◽  
pp. 115-118 ◽  
Author(s):  
Henrik Pedersen ◽  
Stefano Leone ◽  
Anne Henry ◽  
Franziska Christine Beyer ◽  
Vanya Darakchieva ◽  
...  
Keyword(s):  
Growth Rate ◽  
Linear Dependence ◽  
Growth Rates ◽  
Molar Fraction ◽  
High Growth ◽  
High Growth Rate ◽  
Epitaxial Layers ◽  
Single Precursor ◽  
Very High

The chlorinated precursor methyltrichlorosilane (MTS), CH3SiCl3, has been used to grow epitaxial layers of 4H-SiC in a hot wall CVD reactor, with growth rates as high as 170 µm/h at 1600°C. Since MTS contains both silicon and carbon, with the C/Si ratio 1, MTS was used both as single precursor and mixed with silane or ethylene to study the effect of the C/Si and Cl/Si ratios on growth rate and doping of the epitaxial layers. When using only MTS as precursor, the growth rate showed a linear dependence on the MTS molar fraction in the reactor up to about 100 µm/h. The growth rate dropped for C/Si < 1 but was constant for C/Si > 1. Further, the growth rate decreased with lower Cl/Si ratio.

Dislocations and Internal Stresses in Thin Films: A Discrete-Continuum Simulation

1999 ◽  
Vol 578 ◽  
Author(s):  
C. Lemarchand ◽  
B. Devincre ◽  
L.P. Kubin ◽  
J.L. Chaboche
Keyword(s):  
Thin Films ◽  
Critical Stress ◽  
Image Force ◽  
Dislocation Dynamics ◽  
Internal Stresses ◽  
Epitaxial Layers ◽  
Free Standing ◽  
Misfit Stress ◽  
Substrate Interface ◽  
Film Substrate

The plasticity of thin films and layers is of considerable technological interest. For instance, the relaxation of internal stresses in semiconducting epitaxial layers has been the object of many studies [1, 2]. This relaxation is usually treated via the concept of critical thickness, the latter being defined as the maximum layer thickness below which dislocations cannot spontaneously move and relax the internal stresses. The various internal stresses present in epitaxial layers (e.g. the misfit and elastic incompatibility stresses at the film/substrate interface and the image force in a free-standing film) can be computed within a continuum frame. However, the way they influence the motion of a dislocation has not yet been computed, even in a approximate manner. An useful approximation that allows treating the boundary condition at the surface of a free-standing film consists of making use of the concept of image dislocation. Then, the critical stress for moving a dislocation in a free-standing film is the same as that of a capped layer of thickness twice that of the film. To date, models and dislocation dynamics (DD) simulations are available that involve several levels of approximation for the treatment of the dislocation/interface and dislocation/surface interactions [3–7]. For reasons that are not clearly understood, however, these models predict critical thicknesses that are systematically larger than the expected ones. The comparison with experiment is, in addition, made difficult because stresses have to be artificially introduced to replace the internal stresses and approximations have to be done to treat the image stresses. In the present work it is shown that it is now possible to fully account for the contribution of the various sources of internal stresses to the critical stress for the motion of a threading dislocation. This is performed numerically with the help of a hybrid code that combines a DD code for the treatment of the dislocation dynamics and a Finite Element (FE) code for the treatment of the boundary conditions. In what follows, several applications of this discrete-continuum model (DCM) to the study of dislocation motion in epitaxial layers are presented. The motion of a dislocation in a thin film is considered, including the image force and successively adding a misfit stress and an elastic incompatibility stress at the film/substrate interface.

High Uniformity with Reduced Surface Roughness of Chloride Based CVD Process on 100mm 4° Off-Axis 4H-SiC

2012 ◽  
Vol 717-720 ◽  
pp. 93-96 ◽  
Author(s):  
Hrishikesh Das ◽  
Swapna G. Sunkari ◽  
Timothy Oldham ◽  
Janna R. B. Casady ◽  
Jeff B. Casady
Keyword(s):  
Surface Roughness ◽  
Epitaxial Growth ◽  
Growth Rates ◽  
Growth Process ◽  
Process Conditions ◽  
Epitaxial Layers ◽  
High Uniformity ◽  
Highly Uniform ◽  
Reduced Surface

In this work we present the epitaxial growth of 4H-SiC on 100mm 4° off-axis substrates grown in a multi-wafer CVD planetary reactor. Highly uniform epitaxial layers having thickness and doping uniformities of 1.7% and 1.4% respectively were grown in the production reactor with optimized process conditions at 8µm/hr and 30µm/hr growth rates. Process optimizations resulted in epitaxial layers with surface roughness (RMS) of 0.32nm. Epitaxial layers with a thickness of 53µm grown with a 30µm/hr growth process had minimal degradation in surface roughness (RMS of 0.39nm).

Mombe Growth of GaP and its Efficient Photoeniiancement at Low Temperatures

1992 ◽  
Vol 242 ◽  
Author(s):  
Masahiro Yoshimoto ◽  
Tsuzumi Tsuji ◽  
Atsushi Kajimoto ◽  
Hiroyuki Matsunami
Keyword(s):  
Growth Rate ◽  
Laser Irradiation ◽  
Growth Rates ◽  
Low Temperatures ◽  
Epitaxial Layers ◽  
Smooth Surfaces ◽  
Group Iii ◽  
Substrate Temperatures

ABSTRACTGaP epllayers grown at temperatures ranging from 420 to 500°C had smooth surfaces and streaky RHEED patterns. The decomposition of group-III sources of TEGa limits the growth rates of GaP at lower substrate temperatures(<390 °C ). The growth rate of GaP epitaxial layers was efficiently enhanced by N2∼laser irradiation at lower substrate temperatures.

Investigation of single crystals and epitaxial layers (EL) Of SiC by means of real color SEM technique

1990 ◽  
Vol 48 (4) ◽  
pp. 712-713
Author(s):  
E.N. Mokhov ◽  
M.V. Chukichev ◽  
A.D. Roenkov ◽  
G.V. Saparin ◽  
S.K. Obyden ◽  
...  
Keyword(s):  
Characteristic Feature ◽  
Band Gap ◽  
Single Crystals ◽  
Intermediate Layer ◽  
Optoelectronic Devices ◽  
Argon Atmosphere ◽  
Epitaxial Layers ◽  
Inhomogeneous Distribution ◽  
First Case ◽  
Sandwich Method

Investigations were undertaken with SiC, a large-bandgap semiconductor material, that is rather promising for designing different optoelectronic devices. The characteristic feature of SiC is the availability of a large number of modifications, i.e. polytypes, strongly differing in the band-gap. The important problems that stand in the way of mastering SiC are the detectable doping of single crystals and epitaxial structures, the transformation of polytypes, and the structure of the intermediate layer. Crystals of SiC and its EL of 3C, 15R, 6H, 4H polytypes doped with N, Al, Ga and B were investigated. Single crystals were grown by the Leli method at T = 2600-2700°C as plates with basis planes {0001} . Epitaxial layers were grown by the sublimation "sandwich method" at T = 1700-2400°C in a vacuum or in an argon atmosphere.An analysis of the luminescence micrographs in the SEM and of the CL spectra shows that the distribution of impurities and polytype inclusions in single crystals considerably differs from that in EL. In the first case there occurs a striated inhomogeneity of CL across the whole width of the crystal which is obviously connected with an inhomogeneous distribution of dopes. Such a distribution of impurities was not observed in EL.

Growth and Characterization of High-Performance GaN and AlxGa1−xN Ultraviolet Avalanche Photodiodes Grown on GaN Substrates

2007 ◽  
Vol 1040 ◽  
Author(s):  
Russell D. Dupuis ◽  
Dongwon Yoo ◽  
Jae-Hyun Ryou ◽  
Yun Zhang ◽  
Shyh-Chinag Shen ◽  
...  
Keyword(s):  
Defect Density ◽  
Growth Parameters ◽  
Avalanche Photodiodes ◽  
Chemical Vapor ◽  
Device Fabrication ◽  
Breakdown Field ◽  
Structural Quality ◽  
Epitaxial Layers ◽  
Free Standing

AbstractWide-bandgap III-nitride-based avalanche photodiodes (APDs) are important for photodetectors operating in UV spectral region. For the growth of GaN-based heteroepitaxial layers on lattice-mismatched substrates such as sapphire and SiC, a high density of defects is introduced, thereby causing device failure by premature microplasma breakdown before the electric field reaches the level of the bulk avalanche breakdown field, which has hampered the development of III-nitride based APDs. In this study, we investigate the growth and characterization of GaN and AlGaN-based APDs on free-standing bulk GaN substrates. Epitaxial layers of GaN and AlxGa1−xN p-i-n ultraviolet avalanche photodiodes were grown by metalorganic chemical vapor deposition (MOCVD). Improved crystalline and structural quality of epitaxial layers was achieved by employing optimum growth parameters on low-dislocation-density bulk substrates in order to minimize the defect density in epitaxially grown materials. GaN and AlGaN APDs were fabricated into 30μm- and 50μm-diameter circular mesas and the electrical and optoelectronic characteristics were measured. APD epitaxial structure and device design, material growth optimization, material characterizations, device fabrication, and device performance characteristics are reported.

Mombe Growth of GaP and its Efficient Photoeniiancement at Low Temperatures

1992 ◽  
Vol 242 ◽  
Author(s):  
Masahiro Yoshimoto ◽  
Tsuzumi Tsuji ◽  
Atsushi Kajimoto ◽  
Hiroyuki Matsunami
Keyword(s):  
Growth Rate ◽  
Laser Irradiation ◽  
Growth Rates ◽  
Low Temperatures ◽  
Epitaxial Layers ◽  
Smooth Surfaces ◽  
Group Iii ◽  
Substrate Temperatures

ABSTRACTGaP epllayers grown at temperatures ranging from 420 to 500°C had smooth surfaces and streaky RHEED patterns. The decomposition of group-III sources of TEGa limits the growth rates of GaP at lower substrate temperatures(<390 °C ). The growth rate of GaP epitaxial layers was efficiently enhanced by N2∼laser irradiation at lower substrate temperatures.

High growth rates (>30μm/h) of 4H–SiC epitaxial layers using a horizontal hot-wall CVD reactor

2005 ◽  
Vol 285 (4) ◽  
pp. 486-490 ◽  
Author(s):  
R.L. Myers ◽  
Y. Shishkin ◽  
O. Kordina ◽  
S.E. Saddow
Keyword(s):  
Growth Rates ◽  
High Growth ◽  
Epitaxial Layers
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