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X-ray topography is an effective tool to investigate dislocations in semiconductor crystals. Due to low X-ray absorption coefficients of diamond, X-rays can penetrate deep into the crystal. Thus, deep three-dimensional (3D) dislocations are projected on two-dimension (2D) film, which makes dislocation analysis particularly challenging. Dislocation vectors from the films obtained using a set of the same diffraction vectors were identified using topographical and geometrical analyses. The depth and position of the dislocations in a crystal that was projected on a film were determined using geometrical relationship. The proposed analysis method was verified by analyzing several dislocations using four diffraction films. The types of dislocation were identified through Burgers vector analysis.

Several studies have been carried out regarding the influence of dislocations on device characteristics; however, most of them had been limited to pseudo-vertical structures using high pressure high temperature (HPHT) insulating material as the substrate. In this study, we have investigated the influence of dislocations to the devices using vertical structure SBD on p+ HPHT substrate. SBDs were selectively fabricated on specific dislocation areas. The SBD fabricated on the threading dislocation area indicated fatal influence of the dislocation on the device characteristics.

X-ray topography is an effective tool for investigating dislocations in semiconductor crystals. Owing to the low X-ray absorption coefficients of light element materials such as diamond, X-rays can penetrate deep into the crystal. Thus, deep three-dimensional dislocations are projected onto a two-dimensional film, which makes dislocation analysis particularly challenging. The dislocation vectors from the films obtained using a set of the same diffraction vectors were identified using topographical and geometrical analyses. The depth and position of the dislocations in a three-dimensional crystal that was projected onto a two-dimensional film were determined using geometrical relationships. The proposed analysis method was verified by analyzing many dislocations using four diffraction films.

Influence of dislocations on diamond Schottky barrier diode characteristics of vertical structure p- layer/p+ substrate is studied. Devices are intentionally fabricated at locations corresponding to specific dislocations, stacking faults and growth sector boundaries observed using X-ray topography (XRT) prior to device fabrication. Devices fabricated on [001] threading dislocation area, and threading dislocation with stacking fault (SF) areas showed very large leakage current compared with devices without dislocations. Dislocation vectors of four devices having threading dislocations with SFs, are analyzed using XRT images and compared with current to voltage (I–V) characteristics. The number of threading dislocations and their types vary significantly, and there is not much difference in the I–V characteristics. Thus, threading dislocations are fatal to the device characteristics regardless of their dislocation directions, types, and number counts.

Our novel apparatus measures the local Peltier constant at a thermoelectric material microregion. A narrow metal needle probe contacts a sample mounted into a small adiabatic vacuum chamber with a pressure of about 10−4 Pa. A␣stepping-motor-type nano-actuator controls the probe’s contact pressure. We measured DC and AC I–V characteristics at the microcontact to determine thermoelectric properties. We measured I–V characteristics between the probe and a commercial (Bi,Sb)2Te3 surface. Measured values of local Peltier constants are of the same order as the bulk Peltier constant π: ca. 55 mV. They increase with increased contact resistance, suggesting that contact size affects thermoelectricity.