Chepugov A. Regularities of the formation of defect-impurity composition in semiconducting diamond crystals to be used as probes for tunneling microscopes

Dissertation deals with the solving scientific and technical problem of growing semiconducting single crystal diamonds; studying regularities of the formation of de-fect-impurity composition in type IIb diamond single crystals and preparing samples suitable for making scanning tunneling microscope probes. The crystal growth features in Fe-Co-Zr-B-C and Fe-Al-B-C systems at temperatures of 1350-1600 °C and pressure of 6,0-6,5 GPa were considered. It was determined that increase of the crystals amount in a cell leads to a decrease of the separate crystal growth rate. The influence of growing conditions on zonal-sectorial structure of crystals and the possibility to obtain crystals with 80 % {111} faces during crystallization in the Fe-Co-Zr-B-C system at temperatures over 1550 °C and with 100 % in the Fe-Al-B-C system at temperatures over 1450 °C had been established. It had been shown that as the carbon source is doped by B4C (from 1 to 2.5 wt. %) the uncompensated boron concentration changes linearly (from 35 to 87 ppm and 10 to 25 ppm for crystal growth sectors {111} and {100} respectively), the resistivity of growth sector {111} decreases from 3.32 · 105 to 1.65 · 104 Ohm · cm, that makes it possible to use diamonds, whose volume formed with growth sectors {111}, for the manufacture of STM probes. The STM probes with semiconducting diamond tip formed in the Berkovich pyramid shape were produced and tested using reference surfaces.