Silver Spring, MD, United States
Silver Spring, MD, United States

Time filter

Source Type

Ruterana P.,National Engineering School of Caen | Syrkin A.L.,Technologies and Devices International | Monroy E.,CEA Grenoble | Valcheva E.,Sofia University | Kirilov K.,Sofia University
Physica Status Solidi (C) Current Topics in Solid State Physics | Year: 2010

A series of InN layers grown by different techniques has been investigated by transmission electron microscopy, photoluminescence and Raman spectroscopy. The polarity is shown to be determined by the underlying GaN template. In these In polar layers, the c-screw dislocations density is low and that of a-type dislocations is in the high-109 cm-2 range. The dislocation density tends to decrease towards the surface. Along the first 0.5 μm, and particularly in the samples grown by hydride vapour epitaxy, we observe a large number of stacking faults, which probably contribute to the dislocation density reduction. The optical band gap in MBE and MOVPE samples is between 0.6 and 0.7 eV, but that of the HVPE templates is above 1 eV. Estimations from Raman data show that this behaviour correlates well with the residual carrier concentration. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Lacroix B.,CNRS Center for Research on Ions, Materials and Photonics | Chauvat M.P.,CNRS Center for Research on Ions, Materials and Photonics | Ruterana P.,CNRS Center for Research on Ions, Materials and Photonics | Lorenz K.,Technological and Nuclear Institute of Portugal | And 2 more authors.
Journal of Physics D: Applied Physics | Year: 2011

In this work, the damage formation in InN layers has been investigated subsequent to europium implantation at 300 keV and room temperature. The layers of several micrometres were produced by hydride vapour phase epitaxy and used as matrices for ion implantation experiments due to their good crystalline quality. From this investigation, it is shown that InN exhibits a low stability under rare earth ion implantation. Starting at a low fluence of around 5 × 1012 Eu cm-2, an extensive modification of the surface layer takes place. The dissociation of InN and the presence of misoriented nanograins are observed in the damaged area. Analysis by electron diffraction indicates that the nanograins correspond to indium oxide In2O 3. © 2011 IOP Publishing Ltd.


Trademark
Technologies, Devices International and Oxford Instruments | Date: 2010-04-13

Apparatus and instruments, namely, industrial chemical reactors for the production and growth of semiconductor materials; Industrial installations and machines for the production and growth of semiconductor materials.


Jarasiunas K.,Vilnius University | Malinauskas T.,Vilnius University | Nargelas S.,Vilnius University | Gudelis V.,Vilnius University | And 3 more authors.
Physica Status Solidi (B) Basic Research | Year: 2010

We report on nonequilibrium carrier dynamics in a set of hydride vapor phase epitaxy (HVPE) GaN wafers of different thickness (11, 17, 41, 90, and 145 μm) grown on the (0001) c-plane sapphire substrates. Carrier lifetime τR and diffusion length LD were determined by picosecond transient grating and free carrier absorption (FCA) techniques. The nonradiative recombination lifetime increased from 400 ps in the thinnest layer up to 25 ns in the thickest one, and LD varied from 0.24 to 1.9μm, respectively. The τR and LD values in the 145μm-thick HVPE layer are the largest ones reported up to now in bulk GaN at room temperature. The data provided a relationship τRαd3/2 between the carrier lifetime and wafer thickness in ~10-150 mm thickness range. The latter dependence indicated the dramatic decrease of threading dislocation density in the probed subsurface area of the studied wafers from 4×109 to ~106 cm-2. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Usikov A.,Technologies and Devices International | Soukhoveev V.,Technologies and Devices International | Shapovalov L.,Technologies and Devices International | Syrkin A.,Technologies and Devices International | And 8 more authors.
Physica Status Solidi (A) Applications and Materials Science | Year: 2010

This paper reports structural characterization of thick (112̄2)-oriented GaN layers by means of XRD, TEM, and micro-CL. The semi-polar (112̄2) GaN layers were grown on m-plane sapphire substrates by HVPE. Their structural quality improved with thickness. Threading dislocation density of 3×10 8 cm -2 and stacking faults density of 4×10 4 cm -1 were measured at the surface of 20 mm thick (112̄2) GaN layers. The semi-polar GaN layers were used as template substrates to grow InGaN/GaN MQW heterostructures by MOCVD that demonstrated optically pumped lasing at 500 nm wavelength. The results demonstrate the longest wavelength yet reported for a photopumped laser on template substrates. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Scajev P.,Vilnius University | Usikov A.,Technologies and Devices International | Soukhoveev V.,Technologies and Devices International | Aleksiejnas R.,Vilnius University | Jarasinas K.,Vilnius University
Applied Physics Letters | Year: 2011

Time-resolved free-carrier absorption and transient grating techniques were applied to determine carrier lifetimes and diffusion coefficients in a set of hydride vapor phase epitaxy GaN layers of various thickness (from 10 to 145 mu;m). A linear increase in nonradiative carrier lifetime in 80-800 K range found to be in a correlation with decrease of the bipolar carrier diffusion coefficient. This correlation confirmed that recombination rate is governed by carrier diffusive flow to the grain boundaries of columnar defects. A model of diffusion-governed nonradiative lifetime was proposed for fitting the measured lifetime values in the layers of different thickness as well as lifetime dependence on temperature or threading dislocation density. © 2011 American Institute of Physics.


Patent
Technologies and Devices International | Date: 2011-12-28

A method and apparatus for fabricating thin Group III nitride layers as well as Group III nitride layers that exhibit sharp layer-to-layer interfaces are provided. According to one aspect, an HVPE reactor includes one or more gas inlet tubes adjacent to the growth zone, thus allowing fine control of the delivery of reactive gases to the substrate surface. According to another aspect, an HVPE reactor includes both a growth zone and a growth interruption zone. According to another aspect, an HVPE reactor includes a slow growth rate gallium source, thus allowing thin layers to be grown. Using the slow growth rate gallium source in conjunction with a conventional gallium source allows a device structure to be fabricated during a single furnace run that includes both thick layers (i.e. utilizing the conventional gallium source) and thin layers (i.e. utilizing the slow growth rate gallium source).


Loading Technologies and Devices International collaborators
Loading Technologies and Devices International collaborators