Introduction The semiconductor single-crystal CVD diamond (ob-tained from the gas phase during homoepitaxial deposi-tion) is a wide band gap semiconductor with a gap width of 5.5 eV. CVD diamond has unique characteristics-high mobility of charge carriers, high carrier saturation speed, high electric breakdown field, the greatest thermal conductivity, high radiation and chemical resistance. On a combination of properties the CVD diamond is superior to other wide band gap semiconductors and is considered a promising material for the creation of a new generation of high-power and high-frequency electronic devices. The main difficulty in realization of the potential of CVD diamond as an electronic material is the problem of creating charge carriers inside it. Compared with conventional semiconductors, dopants in diamond have deeper energy levels that significantly impede the activation of the do-pant (the degree of ionization of the dopant at room temperature is less than 1%). Thus, in order to create an acceptable level of conductivity, it is necessary to increase the level of doping, but in case of boron doping this leads to a decrease of carriers (holes) mobility in diamond. To solve the problem of boron doping of CVD diamond, an approach based on delta-doping technology is known. A thin layer of diamond heavily doped with boron (hav-ing a thickness of 1-2 nm and concentration of boron atoms higher than 5×10 20 cm-3) is formed inside an un-doped defect-free diamond of high quality. To achieve high electronic properties (obtaining high hole mobility and conductivity of the layer), it is necessary to realize sharp boundaries between the doped and undoped materials. Recently, this problem has been successfully solved [1, 2]. This report provides an overview of the results of studies on the growth of electronic-quality epitaxial layers of diamond, the production of heavily boron-doped layers and the study of their characteristics. Experiments The novel microwave plasma assisted CVD reactor for growth of nanometric boron delta-doped layers with ultra-sharp interfaces between doped/undoped materials was built in IAPRAS [1]. Fig. 1 shows a schematic of the reactor. The main features of the reactor are: 1) rapid gas switching; 2) laminar gas flow; 3) axial symmetric resonant mode-symmetric discharge; 4) slow growth of diamond 40-100 nm/h. We achieve rapid gas switching from one input gas to another by a home-made electronic switch. The residence time of the reactor is approximately 5 s. In developed reactor the diamond deposition regimes in which one obtains thin doped delta layers with thickness of 1-2 nm with concentrations of boron about 5·10 20 cm-3 were found. Typical parameters of the delta layer under these conditions are given in Fig. 2 for the SS6-1 sample, in which the boron concentration is 4.8·10 20 cm-3 and thickness is 1 nm. Measurement of the boron concentration in the grown samples was carried out by the secondary ion mass spectroscopy (SIMS) method using a time of flight SIMS setup (IONTOF TOF.SIMS-5). T...

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We report on building a novel chemical vapor deposition (CVD) reactor for diamond delta‐doping. The main features of our reactor are: a) the use of rapid gas switching system, (b) the reactor design providing the laminar gas flow. These features provide the creation of ultra‐sharp interfaces between doped and undoped material and minimize the prolonged ”tails” formation in the doping profile. It is proved by optical emission spectroscopy that gas switching time is not more than 10 seconds. Using the novel reactor we have grown the nanometer‐thin layers of boron doped diamond. The FWHM of boron concentration profile is about 2 nm which is proved by SIMS. It is shown that the both single delta‐layer and multiple delta‐layers could be grown using the novel CVD reactor. In principle, the reactor could be used for diamond delta doping with other dopants, like nitrogen, phosphorus etc. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)

Results obtained in several experiments on active rf pulse compression at X band using a magnicon as the high-power rf source are presented. In these experiments, microwave energy is stored in high-Q TE 01 and TE 02 modes of two parallel-fed resonators, and then discharged using switches activated with rapidly fired plasma discharge tubes. Designs and high-power tests of several versions of the compressor are described. In these experiments, coherent pulse superposition was demonstrated at a 5-9 MW level of incident power. The compressed pulses observed had powers of 50-70 MW and durations of 40-70 ns. Peak power gains were measured to be in the range of 7:1-11:1 with efficiency in the range of 50%-63%.

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The results of a study of the deposition of silicon-doped epitaxial diamond layers in a microwave CVD reactor to create silicon-vacancy color centers are presented. The relationship between the optical...

The results of studying experimentally the influence of an external dc electric field on the multipactor threshold on the surface of a dielectric (quartz) are presented. In the experiments, a high-Q-factor microwave resonator was excited at the TE 012 mode in the 3-cm wavelength band. The dependence of the breakdown threshold on the value and direction of the electrostatic field is determined. It is found that the external dc field repulsing the electrons from the dielectric surface increases the threshold significantly, whereas the field attracting the electrons decreases it. It is shown that one can manage the multipactor efficiently, namely suppress or initiate it, by changing the direction and intensity of the dc field.