Dynamical X-ray diffraction imaging of voids in dislocation-free high-purity germanium single crystals

Abstract

<jats:p>White-beam X-ray topography has been performed to provide direct evidence of micro-voids in dislocation-free high-purity germanium single crystals. The voids are visible because of a dynamical diffraction contrast. It is shown that voids occur only in dislocation-free parts of the crystal and do not show up in regions with homogeneous and moderate dislocation density. It is further suggested that the voids originate from clustering of vacancies during the growth process. A general method is proposed to verify the presence of voids for any crystalline material of high structural perfection.</jats:p>

Development of Large‐Diameter and Very High Purity Ge Crystal Growth Technology for Devices

“…At the initial development stage, the growth experiments were first optimized to grow 2‐inch diameter HPGe single crystals, and the structural properties of the crystals grown under different gas atmospheres of H 2 and argon (Ar) were investigated and already reported. [ 15 ] As the crystals grown under Ar atmosphere normally do not give rise to high purity, the main interest of this present manuscript is to focus only on the crystals grown under highly pure H 2 . H 2 has large thermal conductivity, lower viscosity, and large convective heat transfer coefficient.…”

“…A representative sketch of a crystal showing the locations where the samples were taken for the EPD analyses and the corresponding For comparison, 2-inch diameter crystals grown initially in the scaled-up system have dislocation densities within the range of 2600-5000 cm −2 as estimated by X-ray topography and etching methods. [15] HRXRD-RC of the 3-inch crystals shows a full-width at half-maximum (FWHM) value of 12 arcsec along the diameter of the wafer. This is the minimum FWHM that could be measured with the present experimental stepup and configurations.…”

Evaluation the nonlinear response function of a HPGe detector for 59 keV to 10.7 MeV gamma-rays using a Monte Carlo simulation and comparison with experimental data

“…It is known that the thickness of dead layer increases with time due to the continuous diffusion of the lithium atoms inside the germanium crystal, particularly if the HPGe detectors were kept at room temperature for several years [36,37]. Such a variable thickness must be taken into account in the characterization and modeling of that dead layer [38][39][40][41]. Since the efficiencies calculated by including the data provided by the manufacturer in the Monte Carlo simulations deviate from the experimental ones [16,36,42,43], an optimization of the dead layer thickness was performed in Monte Carlo simulations to match the calculated efficiencies with the experimental ones [12,16].…”