Wyniki wyszukiwania - BazTech

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Influence of RF ICP PECVD process parameters of diamond-like carbon films on DC bias and optical emission spectra

Oleszkiewicz W, Markowski J, Srnanek R, Kijaszek W, Gryglewicz J, Kovac J, Tlaczala M

Optica Applicata

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2013

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Vol. 43, nr 1

109--115

EN

The work presents the results of a research carried out with PlasmaLab Plus 100 system, manufactured by Oxford Instruments Company. The system was configured for deposition of diamond-like carbon films by ICP PECVD method. The change of an initial value of DC bias was investigated as a function of set values of the generator power (RF generator and ICP generator) in the constant power of the RF generator operation mode. The research shows that the value of DC bias nearly linearly depends on the RF generator power value and is affected only in a small degree by the power of ICP discharge. The capability of an installed OES spectrometer has been used to ensure the same starting conditions for the deposition processes of DLC films. The analysis of OES spectra of RF plasma discharge used in the deposition processes shows that the increase in ICP discharge power value results in the increased efficiency of the ionization process of a gaseous precursor (CH4). The quality of deposited DLC layers was examined by Raman spectroscopy. Basing on the acquired Raman spectra, the theoretical content of sp3 bonds in the structure of the film was estimated. The content is ranging from 30% to 65% and depends on ICP PECVD deposition process parameters.

2

Gallium oxide buffer layers for gallium nitride epitaxy

Korbutowicz R, Wnek J, Panachida P, Serafinczuk J, Srnanek R

Optica Applicata

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2013

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Vol. 43, nr 1

73--79

EN

Gallium nitride (GaN) is very attractive semiconductor material because of its unique properties. The serious matter is a lack of easy access to bulk crystals of GaN. Synthesized crystals are precious and rather small. For these reasons almost all device manufacturers and researchers apply alternative substrates for gallium nitride devices epitaxy and it causes that the technology is intricate. Alternative substrates need buffer layers – their technology is usually complex and expensive. We have proposed a simple method to avoid large costs: applying gallium oxide – monoclinic β-Ga2O3, as the buffer layer, which has structural properties quite good matched to GaN. As the substrates made from single crystal gallium oxide are still hardly available on the market, we have used hydride vapour phase epitaxy (HVPE) GaN epilayers as a starting material. It can be GaN layer under good quality – middle or low. The oxidation process converts top GaN to β-Ga2O3 layer which can release or absorb the strain. Applying such structure in another, second, epitaxy of GaN allows to obtain good quality epitaxial structures using HVPE technique.

3

Technology and properties of GaAs doping superlattices

Ściana B., Radziewicz D., Pucicki D., Tłaczała M., Sęk G., Poloczek P., Misiewicz J., Kováč J., Srnanek R., Christofi A.

Materials Science Poland

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2008

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Vol. 26, No. 1

71--78

EN

Heterojunction and doping superlattices are widely used in many advanced semiconductor devices such as resonant tunnelling diodes, optical modulators, cascade lasers, tunable light emitting diodes and photodetectors. These structures exhibit nonlinear electrooptical properties. Nonlinear processes are governed by the Franz-Keldysh effect and the band-filling effect in the n-i-p-i superlattices and by the quantum-confined Stark effect in the case of n-i-p-i multiple quantum well structures. The paper presents investigations of GaAs n-i-p-i and p-i-p-i doping superlattices grown by atmospheric pressure metal organic vapour phase epitaxy. The properties of the obtained structures were examined using: EC-V method, SIMS spectrometry, photoluminescence and photoreflectance spectroscopy.

4

AlGaAs/GaAs heterojunction phototransistor with Zn delta-doped base region

Ściana B., Radziewicz D., Pucicki D., Tłaczała M., Kovac J., Srnanek R.

Optica Applicata

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2005

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Vol. 35, nr 3

645-650

EN

The paper presents the technology and characterisation of n-p-n AlGaAs/GaAs heterojunction phototransistor (HPT) with a thin (50 nm) Zn delta-doped GaAs base region. Such a construction of the HPT transistor was applied to obtain higher current gain and lower power consumption. The electrical and optical properties of the HPT transistor were examined using electrochemical capacitance-voltage (EC-V) measurements, photovoltage, photocurrent and micro-Raman spectroscopies. The measured and simulated I-U characteristics as well as results of time response measurements are also presented and discussed. All investigations were carried out without a base bias ("floating base").