A5050382645- GaN-based semiconductor devices and materials
- ZnO doping and properties
- Ga2O3 and related materials
- Semiconductor materials and devices
- Semiconductor Quantum Structures and Devices
- Metal and Thin Film Mechanics
- Silicon Carbide Semiconductor Technologies
- Plasma Diagnostics and Applications
- Acoustic Wave Resonator Technologies
- Nanowire Synthesis and Applications
- nanoparticles nucleation surface interactions
- Semiconductor Lasers and Optical Devices
- Thin-Film Transistor Technologies
- Semiconductor materials and interfaces
- Nuclear Materials and Properties
- Muon and positron interactions and applications
- Photocathodes and Microchannel Plates
- Quantum and electron transport phenomena
- Advanced Semiconductor Detectors and Materials
- Thermal properties of materials
- Ammonia Synthesis and Nitrogen Reduction
- Strong Light-Matter Interactions
- Glass properties and applications
- Advanced Chemical Physics Studies
- Solidification and crystal growth phenomena
Institute of High Pressure Physics
2015-2025
Polish Academy of Sciences
2012-2023
TopGaN (Poland)
2008-2016
Radboud University Nijmegen
2008
Center for High Pressure Science and Technology Advanced Research
1996
Homoepitaxial growth of high structural quality and high-purity thick gallium nitride layers by crystallization from vapor phase (hydride epitaxy (HVPE)) on 1, 1.5, 2 inch substrates obtained a solution (ammonothermal) method is presented. Advantages disadvantages both technologies are described in detail. Structural, optical, electrical, thermal properties grown the demonstrated compared to ammonothermally material. It shown that synergy these two methods can create new opportunities for an...
Perspectives about growth of bulk gallium nitride crystals, fabricating high structural quality wafers and the market demand for them are presented. Three basic crystal technologies, halide vapor phase epitaxy, sodium flux, ammonothermal, described. Their advantages disadvantages, recent development, possibilities discussed. The main difficulty with crystallization thick GaN is determined. Some new solutions proposed. It shown that only on native seeds will ensure proper progress. New ideas...
Abstract GaN crystals were grown by hydride vapor phase epitaxy (HVPE) and doped with C. The seeds high-structural-quality ammonothermally crystallized GaN. highly resistive at 296 K of high structural quality. High-temperature Hall effect measurements revealed p-type conductivity a deep acceptor level in the material an activation energy 1 eV. This is good agreement density functional theory calculations based on hybrid functionals as presented Van de Walle group. They obtained ionization...
It is well known that ion implantation one of the basic tools for semiconductor device fabrication. The process itself damages, however, crystallographic lattice semiconductor. Such damage can be removed by proper post-implantation annealing implanted material. Annealing also allows electrical activation dopant and creates areas different types in a However, such thermal treatment particularly challenging case gallium nitride since it decomposes at relatively low temperature (~800 °C)...
We have used positron annihilation, secondary ion mass spectrometry, and photoluminescence to study the point defects in GaN grown by hydride vapor phase epitaxy (HVPE) on bulk crystals. The results show that N polar growth incorporates many more donor acceptor type impurities also Ga vacancies. Vacancy clusters with a lifetime τD=470±50ps were found near surfaces of both HVPE layers
Dislocations in GaN single crystal were studied by means of spectral cathodoluminescence (CL) mapping and defect selective etching. We show that the c-type screw dislocations are not recombination active. The strength a- (a+c)-type is influenced impurity gettering. While fresh exhibit a CL contrast 0.01–0.05 accordance with intrinsic dislocation states, grown 0.25. From analysis maps, we find impurities such as oxygen silicon depleted surrounding dislocations. explain increased reduced...
Crystallization of GaN by hydride vapor phase epitaxy (HVPE) on ammonothermally grown seed crystals is described. The initial growth conditions for HVPE are determined and applied further bulk growth. Smooth layers up to 1.1 mm thick excellent crystalline quality, without cracks, with low dislocation density obtained. Preparation the free-standing HVPE-GaN crystal slicing structural optical quality resulting wafer presented.
A computational fluid dynamics simulation was developed for the growth zone of gallium nitride crystallized using alkaline ammonothermal method, considering geometry seed crystals and installation setup. The model focuses on temperature velocity distributions, revealing turbulent transient flow characteristics. Significant findings include effect crystal thickness changes, as well relationship between distribution rate. results indicate that variations in thermal fields affect uniformity...
Gallium vacancies and negative ions are observed in GaN bulk crystals by applying positron lifetime spectroscopy. The concentration of Ga decreases with increasing Mg doping, as expected from the behavior VGa formation energy a function Fermi level. correlates that impurities determined secondary ion mass spectrometry. We thus attribute to MgGa−. charge suggests doping converts n-type semi-insulating mainly due electrical compensation ON+ donors MgGa− acceptors.
X-ray topography defect analysis of entire 1.8-inch GaN substrates, using the Borrmann effect, is presented in this paper. The wafers were grown by ammonothermal method. effect anomalous transmission could be applied due to low density substrates. It was possible trace process and growth history crystals detail from their pattern imaged. Microscopic defects such as threading dislocations, but also macroscopic defects, for example dislocation clusters preparation insufficiency, traces facet...
We investigate properties of doping-induced metal-insulator transition in GaN:Si by means electron spin resonance and Hall effect. While increasing the doping concentration, Si-related bands are formed below bottom GaN conduction band. The D0 band single-occupied Si donor sites is centered 27 meV band, D- double-occupied states at 2.7 Strong damping magnetic moment occurs due to filling concentrations approaching transition. Simultaneously, shortening relaxation time limited lifetime...
Abstract It is demonstrated in this paper that 1.9‐mm‐thick gallium nitride grown by Hydride Vapor Phase Epitaxy (HVPE) on an ammonothermally GaN seed can reproduce the structural, terms of defects, properties seed. The etch pit density and its correlation to threading dislocation ammonothermal substrate HVPE‐GaN layer presented analyzed. However, it has recently been observed for thicker than 2 mm some additional defects are formed new material. Therefore, three HVPE growth runs were...
An influence of doping with iron and manganese on GaN crystallized by halide vapor phase epitaxy is described in this work. This a continuation previous work where solid was used as metal precursor semi-insulating co-doped crystallized. In paper, metals the highest purity were used. The acceptors (iron manganese) incorporated separately order to compensate unintentional donors present undoped crystals. Native wafers seeds. doped samples examined terms their structural electrical properties....
The influence of the miscut angle GaN substrate on compositional and optical properties InxGa1−xN epilayers (0.05<x<0.1) was examined using x-ray diffraction, photoluminescence (PL), cathodoluminescence, Z-contrast scanning electron microscopy. We show that single atomic steps bunch during growth InGaN form macrosteps. Indium is incorporated differently at treads risers these macrosteps, which causes layer to decompose induces formation striations. Since step density increases...