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• IMPULSE CHARACTERISTICS OF SILICON STRUCTURES WITH N-P JUNCTION IRRADIATED BY PROTONS

  N.М. Bogatov, V.S. Volodin, L.R. Grigoryan, А.I. Kovalenko, М.S. Kovalenko

  2022-11-01

  Abstract ▼

  Currently, methods are being actively developed to create semiconductor structures with desired
  properties by irradiation with ionizing particles (radiation defect engineering). The interaction
  of radiation defects with impurities, dislocations and other structural defects causes a change in the
  properties of semiconductors and semiconductor devices. Irradiation with protons makes it possible
  to controllably create radiation defects with a distribution maximum in a pre-calculated region. The
  aim of this work is to analyze the effect of irradiation with low-energy protons on the impulse characteristics
  of silicon structures with an n+-p junction. The task is to determine the effective lifetime  of
  charge carriers in the space charge region (SCR) of the n+-p junction. The n+-p-p+-structures made
  of silicon grown by the Czochralski method, irradiated from the side of the n+-layer by a low-energy
  proton flux at sample temperatures of 300 K and 83 K were studied. To measure the impulse characteristics,
  bipolar rectangular voltage pulses with a constant amplitude of 10 mV and a frequency of
  1 MHz were used. The experimental data are explained using models of nonstationary charge carrier
  transport in inhomogeneous semiconductors and the formation of radiation defects in silicon underthe action of protons. Depth distributions of the average number of primary radiation defects are
  calculated: interstitial silicon, vacancies, divacancies created by one proton per unit length of the
  projective path. It is shown that irradiation with protons with a dose of 1015 cm2 and an energy of
  40 keV does not change the value of , but with an energy of 180 keV creates a region with an effective
  lifetime of 5.5108 s in the SCR of the n+-p junction.

• NOISE GENERATION METHOD BASED ON A SET OF NOISY IMAGES WITHOUT CLEAN EXAMPLES

  А.S. Kovalenko , Y. М. Demyanenko

  243-254

  2025-11-10

  Abstract ▼

  In this work, a novel method is proposed for noise generation from noisy images that does not require aligned pairs of clean and noisy data. Unlike traditional approaches demanding matched image sets or a priori noise models, the developed technique models complex noise characteristics intrinsic to specific CMOS sensors solely from observed noisy data. Noise synthesis is achieved via a U‑Net‑like generative adversarial architecture based on StyleGANv2, featuring a modified discriminator conditioned on camera parameters and input image metadata. Special emphasis is placed on preserving the spatial–color structure and textural details of each image, enforced through a dedicated loss function that ensures fidelity to the original color rendering and fine-grained patterns. Training of the noise generator is performed without any paired clean and noisy images, which proves particularly valuable when handling real-world datasets acquired from multiple camera models under varied lighting conditions. The experimental section presents a detailed comparative analysis of the synthesized images using PSNR and SSIM metrics, along with an evaluation of the noise distribution based on intensity statistics and spectral characteristics. It is demonstrated that the generated dataset functions effectively as a standalone training corpus for denoising neural networks and, when combined with a real dataset (e.g., SIDD), yields further enhancements in denoising performance. Results indicate that combined training on the union of generated and real examples produces an average PSNR improvement of 1.5 dB compared to existing methods reliant on aligned data. Independence from the specific optical characteristics of any given sensor significantly broadens the method’s applicability. These findings confirm the utility of the proposed approach for realistic noise synthesis and removal in scenarios lacking clean reference images, and they open avenues for future research into adaptive noise-model generation

• MODELING THE ELECTRIC FIELD OF A SILICON N-I-P NANOSTRUCTURE

  N.М. Bogatov , V. S. Volodin , L.R. Grigoryan , М. S. Kovalenko

  123-133

  2025-11-10

  Abstract ▼

  Distribution of ionized impurities, electrons, holes determines the structure, physical properties, performance characteristics of semiconductor devices. The role of surface electron states is negative, the degree of their influence on the characteristics of the device depends on the features of the structure. Reducing the size of semiconductor devices is a modern trend in improving electronics. The influence of surface states on the properties of nanoscale objects increases with decreasing size. The object of the study is the electric field of a silicon n-i-p nanostructure. The purpose of the study is to analyze the influence of surface states on the internal electric field of a silicon n-i-p nanostructure. Research objectives: 1 – Calculate numerically, taking into account the surface states, the potential and electric field strength, the concentration of donors and acceptors in a silicon n-i-p nanostructure with a diffusion doping profile.
  2 – Determine the influence of the thickness of the n-i-p nanostructure and the density of surface states on the potential and electric field strength. 3 – Determine the composition of the space charge region of the n-i-p nanostructure with the minimized influence of surface states. The calculation method is based on the numerical solution of the Poisson equation taking into account the surface states and boundary conditions, including the condition of the general electroneutrality of the sample. As a result, the distributions of the potential and electric field strength were obtained for different values of the nanostructure thickness and the density of surface states. It is shown that charged surface states change the potential and electric field strength not only in the surface region, but also in the volume of the nanostructure. The value of the strength in the base increases with decreasing thickness, this value decreases if the density of surface states exceeds 10¹³ cm^–2. Reducing the density of surface states to 10¹² cm^–2 eliminates the surface potential barrier created by them. The space charge region consists of 5 parts: a region of positive charge created by ionized donors, a region enriched in electrons, a region depleted in charge carriers, a region enriched in holes, and a region of negative charge created by ionized acceptors

• INFLUENCE OF SURFACE STATES ON THE ELECTRIC FIELD OF THE N-P JUNCTION

  N.M. Bogatov, V.S. Volodin, L.R. Grigoryan, М.S. Kovalenko

  2024-08-12

  Abstract ▼

  The structure and properties of semiconductor devices largely depend on the distribution of the internal
  electric field, which is created by the distribution of ionized impurities. One of the methods for the controlled
  introduction of donors and acceptors is their diffusion into the bulk of the semiconductor. The existence
  of surface electronic states in the band of forbidden energies has an uncontrollable effect on the distribution
  of the electric field in the surface region. The purpose of the study is to analyze the influence of surface
  states on the distribution of the electric field in a diffusion n-p junction. Research objectives. 1 – Develop an
  algorithm for the numerical solution of the Poisson equation, taking into account the general electrical neutrality
  of the n-p junction and the density of surface states in the emitter. 2 – Calculate numerically the distributions
  of electric potential, electric field strength, electron and hole concentrations in a diffusion n-p junction.
  3 – Analyze the influence of surface states on the change in the internal electric field and the rate of
  surface recombination of nonequilibrium charge carriers. As a result, the influence of surface states on the electric field distribution in a diffusion n-p junction in silicon was numerically simulated. The model is based
  on a numerical solution of the Poisson equation with boundary conditions that include the condition of the
  overall electrical neutrality of the sample. It is shown that the density of electronic states on the emitter surface
  creates a narrow range of electric charge density distribution. The maximum value of the modulus of the
  electric field strength in this region exceeds the similar value in the n-p junction by three times or more. The
  electric field strength caused by the surface charge directs minority charge carriers towards the surface. This
  increases the effective rate of their recombination. Reducing the surface charge density or changing its sign
  is one of the tasks of semiconductor device technology.