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EN
The article presents the results of diameter mapping for circular-symmetric disturbance of homogeneity of epitaxially grown InAs (100) layers on GaAs substrates. The set of acceptors (beryllium) doped InAs epilayers was studied in order to evaluate the impact of Be doping on the 2-inch InAs-on-GaAs wafers quality. During the initial identification of size and shape of the circular pattern, non-destructive optical techniques were used, showing a 100% difference in average roughness between the wafer centre and its outer part. On the other hand, no volumetric (bulk) differences are detectable using Raman spectroscopy and highresolution X-ray diffraction. The correlation between Be doping level and circular defect pattern surface area has been found.
EN
Careful selection of the physical model of the material for a specific doping and selected operating temperatures is a non-trivial task. In numerical simulations that optimize practical devices such as detectors or lasers architecture, this challenge can be very difficult. However, even for such a well-known material as a 5 μm thick layer of indium arsenide on a semiinsulating gallium arsenide substrate, choosing a realistic set of band structure parameters for valence bands is remarkable. Here, the authors test the applicability range of various models of the valence band geometry, using a series of InAs samples with varying levels of p-type doping. Carefully prepared and pretested the van der Pauw geometry samples have been used for magneto-transport data acquisition in the 20-300 K temperature range and magnetic fields up to ±15 T, combined with a mobility spectra analysis. It was shown that in a degenerate statistic regime, temperature trends of mobility for heavy- and light-holes are uncorrelated. It has also been shown that parameters of the valence band effective masses with warping effect inclusion should be used for selected acceptor dopant levels and range of temperatures.
PL
W pracy zwrócono uwagę na potrzebę rozwoju technik do precyzyjnego parametryzowania wielokanałowego transportu nośników ładunku, mających fundamentalne znaczenie dla efektywnego projektowania przyrządów półprzewodnikowych. Przedstawiono aktualny stan rozwoju tych technik pomiarowych w Wojskowej Akademii Technicznej, oraz przykładowe rezultaty dla struktur półprzewodnikowych, otrzymywanych techniką epitaksji z wiązek molekularnych (MBE).
EN
The paper highlights the need to develop techniques for the precise parameterization of multi-channel charge carrier transport, which are of fundamental importance for the effective design of semiconductor devices. The current state of development of these measurement techniques at the Military University of Technology is presented, as well as exemplary results for semiconductor structures obtained by molecular beam epitaxy (MBE).
PL
W niniejszym artykule poświęcono uwagę procesowi mokrego trawienia chemicznego warstw epitaksjalnych InAs. Do procesu wprowadzono modyfikację, polegającą na wykonaniu trawienia w sposób cykliczny, przy założonych całkowitych czasach procesu. Zbadano wpływ ilości cykli w procesie mokrego trawienia chemicznego na głębokość trawienia oraz chropowatość strawionej warstwy.
EN
The article focuses on the wet chemical etching process of InAs epitaxial layers. A modification to the process was introduced, consisting in carrying out the etching in a cyclical manner, with the assumed total etching times. The influence of the number of cycles in the process on the etch depth and etched layer roughness was investigated.
PL
Niniejsza praca porusza zagadnienie charakteryzacji warstw epitaksjalnych arsenku indu (InAs) pod kątem jednorodności przestrzennej. Badania przeprowadzone w pracy zostały oparte na trzech metodach charakteryzacji: wysokorozdzielczej mikroskopii optycznej, mikroskopii sił atomowych i spektroskopii Ramana. Obiektem badań były warstwy epitaksjalne InAs na podłożach arsenku galu (GaAs), które zostały wytworzone metodą epitaksji z wiązek molekularnych (MBE).
EN
This thesis deals with the characterization of epitaxial layers of indium arsenide (InAs) in terms of spatial homogeneity. The research conducted in the paper was based on three characterization methods: high-resolution optical microscopy, atomic force microscopy and Raman spectroscopy. The subject of the research were epitaxial layers of InAs on gallium arsenide (GaAs) substrates, which were produced by the method of molecular beam epitaxy (MBE).
EN
A revision of the standard approach to characterization of thin-semiconductor-layer Hall samples has been proposed. Our results show that simple checking of I(V) curve linearity at room temperature might be insufficient for correct determination of bias conditions of a sample before measurements of Hall effect. It is caused by the nonlinear behaviour of electrical contact layers, which should be treated together with the tested layer a priori as a metal-semiconductor-metal (MSM) structure. Our approach was examined with a Be-doped p-type InAs epitaxial layer, with four gold contacts. Despite using full high-quality photolithography a significant asymmetry in maximum differential resistance (Rd) values and positions relative to zero voltage (or current) value was observed for different contacts. This suggests that such characterization should be performed before each high-precision magneto-transport measurement in order to optimize the bias conditions.
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