Study of Ga 2 O 3 deposition by MOVPE using trimethylgallium and oxygen was performed in a wide temperature range. It was found that for Ga 2 O 3 deposition rate vs temperature dependence is very close to the TMGa pyrolysis in nitrogen. Kinetically-limited range for these processes corresponds to 550-700 o C, that is 150 o C higher, then for GaN deposition in the same reactor. Keywords: gallium oxide, MOVPE

В докладе показаны актуальные результаты разработки отечественной технологии выращивания гетероструктур на основе нитрида галлия (GaN) на сверхвысокоомных эпитаксиальных структурах кремния диаметром 150 мм. Получены структуры Ga(Al)N/Si диаметром до 150 мм с подвижностью электронов в 2DEG более 1500 см2В-1с-1, изготовлены тестовые транзисторы GaN HEMT с напряжением отсечки порядка -6,5 В, максимальным током стока насыщения 570 мА/мм, крутизной транзисторов не менее 100 мСм/мм и пробивным напряжением более 200 В.

A technique and technology for manufacturing both LED chips and packaged LEDs from AlInGaN/GaN heterostructures grown on novel SiC/Si substrates synthesized by the method of matched substitution of atoms is described. We have studied the current-voltage characteristics, electroluminescence spectra, and dependence of output power and external quantum efficiency on the current. It is shown that the presence of pores in the SiC/Si substrate, which are naturally formed during its growth, leads to a significant increase in the quantum efficiency of LEDs compared with the quantum efficiency of LEDs fabricated on silicon without a SiC sublayer.

Study of Ga2O3 deposition by MOVPE using trimethylgallium and oxygen was performed in a wide temperature range. It was found that for Ga2O3 deposition rate vs temperature dependence is very close to the TMGa pyrolysis in nitrogen. Kinetically-limited range for these processes corresponds to 550-700 C, that is 150 C higher, then for GaN deposition in the same reactor.

Continuous monitoring of patient’s state in intensive care units is crucial for displaying critical conditions and identifying signs of clear consciousness. Traditional monitoring on a bedside monitor represents digital value on the screen and has several shortcomings. The observer’s perception of digital information is limited by visual acuity and affects the speed of decision-making. The radio frequency range is increasingly overloaded with the development of Internet of Things devices. It leads to numerous errors in the transmitted data. The developed system is aimed at the comprehensive elimination of the shortcomings through available means. An understandable visualization system is preferred for prompt recognition of changes in the patient’s state, increasing the speed of perception of the observer, and receiving information in the form of a data set. A data transmission system via optical wireless communication is relevant for duplicative channel for displaying and eliminating the shortcomings of systems operating in the radio frequency range. The system being developed is universal and can be used in a wide range of professional fields. In particular, if the use of the radio frequency range is limited and the stability of the data transmission channel to electromagnetic interference is essential.

Разработана и экспериментально подтверждена концепция установок для МОС-гидридной эпитаксии III-N-гетероструктур с горизонтальными реакторами и принципиально новыми инжекторами газов. Установки оптимизированы для решения различных задач, в том числе для выращивания гетероструктур для электронных применений.

Light-emitting III–N heterostructures are grown by gas-phase epitaxy from organometallic compounds on SiC/Si (111) templates (substrates) formed using matched atomic substitution. Investigations of the optical and structural properties of heterostructures are carried out in order to reveal the formation of defects in the structures. It is shown that such heterostructures exhibit specific features of the growth of the (Al,Ga)N buffer layer associated with the presence of pores in Si under the SiC/Si interface. The use of an optimized buffer layer design makes it possible to significantly reduce the dislocation density and form an active region with good structural quality.

С использованием отечественной установки МОС-гидридной эпитаксии Dragon-125 разработана технология выращивания НЕМТ-структур на основе AlGaN и InAlN с намеренно легированными изолирующими буферными слоями и in-situ Si3N4-покрытиями. Изготовлены НЕМТ-транзисторы и измерены их параметры.

Light emitting III-N heterostructures were grown by metalorganic chemical vapor deposition on the SiC/Si (111) templates (substrates) formed by the method of matched substitution of atoms. Investigations of the optical and structural properties of heterostructures were carried out in order to reveal the formation of defects in the structures. It is shown that features of the growth of the (Al, Ga)N buffer layers in such structuresare associated with the presence of pores in the Si substrate under SiC/Si interface. Applying of the optimal design of the buffer layer allows significantly reduce the dislocation density and form active region with high structural quality.

The technique and technology for fabricating both LED chips and packaged LEDs based on InGaN/GaN heterostructures grown on novel SiC/Si substrates synthesized by the method of matched atomic substitution have been described. The current-voltage characteristics, luminescence spectra, and the current dependences of output power and external quantum efficiency have been studied. It is shown that the presence of pores naturally formed in the SiC/Si substrate during its growth leads to a substantial increase in the quantum efficiency of LEDs in comparison with that of LEDs fabricated on silicon without a SiC sublayer.

Optical properties of a structure with a periodic system of 100 InGaN quantum wells (QWs) separated by non-tunneling GaN barriers have been investigated at room temperature. The structure periodicity corresponded to the Bragg diffraction condition at the frequency of the QW excitons. Numerical modeling using transfer matrices gave a quantitatively accurate fit of the experimental results. The model included the resonance response of A, B, and C excitons in QWs and an optical absorption tail in the barriers and buffer layer. We have determined the radiative and non-radiative broadening of the excitons in the InGaN QWs.

Представлены состав, описание основных узлов и принцип работы экспериментального образца установки «Эпифаз ТМ 200-01» газофазной эпитаксии из металлоорганических соединений (ГФЭ МОС) для роста III-N-гетероструктур на подложках диаметром до 200 мм

Growth of GaN layers by MOVPE on sapphire substrates at various pressures, including above atmospheric, was studied. It is shown that epitaxy at higher pressures does not change the crystal perfection of the layers, the electron mobility, and the impurities incorporation, but leads to the formation of a surface with a smaller lateral scale of inhomogeneities. The epitaxy pressure also affects the ratio of the intensity of the band-edge and impurity-related lines in the photoluminescence spectra and the leakage currents in the reverse-biased Schottky barrier.

Продемонстрированы новые результаты разработки отечественной технологии Ga(Al)N-on-Si. Разработка ведется АО «Эпиэл» в тесном сотрудничестве с НТЦ микроэлектроники РАН. Получены первые отечественные гетероэпитаксиальные структуры Ga(Al)N/Si диаметром 100 мм для HEMT-транзисторов с подвижностью электронов в канале 2DEG выше 1500 см2В-1с-1, выращенные на сверхвысокоомных эпитаксиальных структурах Si на МОГФЭ-системе Dragon-125, разработанной в НТЦ микроэлектроники РАН.

By transmission electron microscopy are studied two buffer structures based on AlGaN alloys doped with silicon and don't. The structures were grown on (111) orientated Si substrates by metal-organic vapour-phase epitaxy with consistently decreasing Al content. It is found that noticeable threading dislocation density reduction took place in intermediate layers at changing Al concentration from 32 to 23%. A phase decay and a composition modulation in growth direction in AlGaN layers with Al content 32, 23, 12 and 4% are observed. A model of the layers structure in the composition modulation area is proposed.

AbstractThe results obtained in a study of the synthesis of n ^+-GaN layers by plasma-assisted molecular-beam epitaxy on GaN/ c -Al_2O_3 templates are reported. In particular, a method is developed for the pre-epitaxial cleaning of the GaN surfaces of templates to remove foreign atoms. It is shown that, to form GaN layers of comparatively good quality, including those doped with silicon up to ~4 . 6 × 10^19 cm^–3, GaN template surfaces should be pre-epitaxially cleaned in a flow of activated nitrogen particles, with the substrate temperature increased from T _ S = 400 to 600°C and the substrate surface subsequently exposed to a flow of activated nitrogen at a fixed value of T _ S = 600°C for 1 h. After that the substrate temperature should be raised to T _ S = 700°C and the GaN surface finally cleaned by means of a procedure for gallium deposition/desorption.

Surface morphology and conductivity properties of semiinsulating GaN epitaxial layers are studied. Improvement of insulating properties with carbon or iron doping level increase is limited by morphology deterioration. Morphology development is different for these two cases. Co-doping with carbon and iron allows keeping planarity with significant improvement of insulating properties.

AbstractA fractal-percolation system that includes extended defects and random fluctuations in the alloy composition is formed during the growth of device structures based on Group-III nitrides. It is established that the specific features of this system are determined not only by the growth conditions. It is shown that the diversity of the electrical and optical properties of InGaN/GaN LEDs (light-emitting diodes) emitting at wavelengths of 450–460 and 519–530 nm, as well as that of the electrical properties of AlGaN/GaN HEMT (high-electron-mobility transistor) structures, is due to modification of the properties of the fractal-percolation system both during the growth process and under the action of the injection current and irradiation. The influence exerted by these specific features on the service life of light-emitting devices and on the reliability of AlGaN/GaN HEMT structures is discussed.

A fractal-percolation system that includes extended defects and random fluctuations in the alloy composition is formed during the growth of device structures based on Group-III nitrides. It is established that the specific features of this system are determined not only by the growth conditions. It is shown that the diversity of the electrical and optical properties of InGaN/GaN LEDs (light-emitting diodes) emitting at wavelengths of 450–460 and 519–530 nm, as well as that of the electrical properties of AlGaN/GaN HEMT (high-electron-mobility transistor) structures, is due to modification of the properties of the fractal-percolation system both during the growth process and under the action of the injection current and irradiation. The influence exerted by these specific features on the service life of light-emitting devices and on the reliability of AlGaN/GaN HEMT structures is discussed.

AlGaN/AlN/GaN and InAlN/AlN/GaN structures with 2D electron gas have been grown on sapphire substrates by metal-organic vapor-phase epitaxy. The suppression of the parasitic conductivity of buffer GaN layers was provided either by intentionally raising the density of edge dislocations or by doping with iron (GaN:Fe). It was shown that using GaN buffer layers with a better crystal perfection and more planar surface results in the electron mobility in the 2D channel for carriers becoming 1.2–1.5 times higher.