Ion implantation is a key technology without alternative for doping silicon carbide SiC in the manufacturing processes of SiC devices. SiC technology has a number of distinctive features in ...comparison with Si-ion doping technology. This paper provides a systematic analysis of modern technical solutions aimed at the formation of local doped regions by the method of ion implantation for various purposes for SiC-based high-power electronic devices. The results of research conducted at the St. Petersburg State Electrotechnical University LETI are presented. This research is focused on the development and selection of modes of aluminum- and phosphorus-ion implantation into 4H-SiC structures that provide specified concentrations of doping impurities and geometric dimensions of local ion-doped regions. The developed ion-implantation modes are successfully implemented in the manufacture of samples of high-power 4H-SiC metal–insulator–semiconductor (MIS) transistors with operating voltages of up to 1200 V.
Currently, chemical gas deposition is the main method for producing high-quality and reproducible epitaxial layers for commercial silicon carbide (SiC) power devices. Based on the experience of the ...Electrotechnical University LETI in the synthesis of single-crystalline SiC, an analysis of the current state of silicon carbide gas phase epitaxy (CVD) technology is carried out. It is shown that modern CVD reactors allow growth processes of high-quality SiC epitaxial structures with the following parameters: substrate diameter of up to 200 mm; epitaxial layer thicknesses of 0.1 to 250 μm; and
n
- and
p
-type layers with doping levels in the ranges 10
14
–10
19
cm
–3
and 10
14
–10
20
cm
–3
, respectively. At the same time, setting up the technology of the reproducible high-quality growth of epitaxial layers is an individual task for a particular type of reactor. A detailed consideration of the technological factors presented in this paper is required, which in the end determine the achievable parameters of SiC-epitaxial products.
The possibility to increase the responsivity of 4
H
-SiC
p
+
–
n
–
n
+
-photodiodes by varying the thickness of the
p
+
-epilayer has been studied. It is shown that the thinning of the upper epilayer ...by RIE with the use of metal contacts as a mask makes it possible to control both the maximum responsivity and the spectral dependence of the responsivity of photodiodes and does not lead to degradation of dark electrical characteristics.
This work has determined the peculiarities of structure and phase transformations at various initial temperatures (–129…548°С) and high deformation rates (448–530 m/s) of shock-wave loading in the ...austenitic nitrogen-containing steel KH20N6G11M2AFB (0.4N–20Сr–6Ni–11Mn–2Mo–V–Nb). The cyclic γ → ε → γ transformation is observed in the course of shock-wave loading at 20–203°С, which causes the phase naklep of austenite and the possible occurrence of the shape memory effect in the regions of deformation localization.
Abstract
Longitude sectorality and latitudinal zonality of morpholithogenesis on the coast of Sakhalin is the result of the unique geographical position of the island, which is a zone of mutual ...influences and interactions of neighboring geosystems of the subarctic Sea of Okhotsk and the moderately cold northern part of the Sea of Japan – a contact geographical structure. Based on the digitizing of maps of morphogenetic types of shores, modern morpholithodynamic settings and lithological complexes of the coast, geomorphological and morphodynamic differences of the shores of Sakhalin Island are shown, the eastern shores of which have a subarctic appearance, and the western shores are washed by the temperate sea.
To assess the effectiveness and safety of Erenumab, a monoclonal antibody to calcitonin gene-related peptide receptors, in patients with high-frequency episodic migraine (HFEM) in real-life study.
35 ...patients with HFEM without aura (≥8-14 attacks per month) (30 females, mean age 32.4±8.1) received monthly subcutaneous administration of Erenumab 70 mg for 3 months. The primary endpoint was the change in monthly migraine days (MMDs) from baseline, the secondary endpoint was the proportion of patients who achieved a 50% reduction in the number of days with headache. The change in pain intensity, change in the number of days of use of acute migraine-specific medication, the effect on daily activity (HIT-6 scale, MIDAS), anxiety and depression (the Hospital Anxiety and Depression Scale) were assessed.
At the end of the third month Erenumab decreased MMDs by 5±3.6 (
=0.00000). A 50% reduction in the mean number of migraine days per month was achieved for 60% of patients, the intensity of headache according to the visual analogue scale from 8±1.2 points to 5±2 points (
=0.00000), monthly analgesics intake passed from 11±7 to 4.5±3.7 (
=0.000001). 25.7% of patients did not respond to treatment, showing less than a 30% decrease in the number of days with headache. A decrease in pain intensity correlated with a decrease in anxiety (from 8±4 to 6±4 points (
=0.003)) and depression (from 6±4 to 4±3 points (
=0.0004)) according to HADS, reduced HIT-6 scale from 65±6 to 55±7 points (
=0.00000) and MIDAS from 45 33; 67 points to 16 5; 33 (
=0.000004)). Patients reported good tolerability of Erenumab. 25.7% of patients noted a tendency to constipation. No patient discontinued treatment due to adverse events.
Real-life study confirmed the efficacy and safety of Erenumab in the treatment of HFEM, a decrease in the severity of comorbid anxiety and depression, and social maladjustment.
The experimental data on the development of natural disturbances during the laminar-turbulent transition in the boundary layers of a flat plate and a swept wing with a supersonic leading edge at Mach ...2 and 2.5 are analyzed. Data are obtained using a hot-wire anemometer in the automatic scanning mode for overheating of the probe. The levels of pulsations of mass flow and disturbances of total temperature are determined using the modified diagrammatic method of Kovasznay taking into account the coefficient of correlation. It was found that at all stages of the laminar-turbulent transition of the flow in the boundary layer, the ratio of the levels of pulsations of the total temperature and pulsations of the mass flow and the correlation coefficient remain almost constant.
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