Electrical Properties of High-Quality Synthetic Boron-Doped Diamond Single Crystals and Schottky Barrier Diodes on Their Basis

摘要

The temperature dependences of the specific resistance and Hall coefficient of high-quality synthetic boron-doped diamond single crystals grown via a high-pressure high-temperature method are studied. The concentration of acceptors in the (001) cut plates was varied in a range of 2 x 10(15)-3 x 10(17) cm(-3) by varying the concentration of boron in the growth mixture (0.0004-0.04 at %). Thin rectangular plates with the uniform concentration of boron and free from extended structural defects are cut out by a laser after the X-ray topography and mapping of UV luminescence. The concentrations of donors and acceptors in the samples are calculated from the data of the Hall effect and capacitance-voltage characteristics. The obtained results correlate with the concentration of boron in the growth mixture. The minimum compensation ratio of acceptors with donors (below 1%) is observed in the crystals grown with the concentration of boron in the growth mixture of 0.002 at %. The ratio increases when the amount of boron is increased or decreased. The samples grown at such a concentration of boron have the maximum mobility of charge carriers (2200 cm(2)/(V s) at T = 300 K and 7200cm(2)/(V s) at T = 180 K). The phonon scattering of holes dominates throughout the range of temperatures (180-800 K), while the scattering by point defects (neutral and ionized atoms of the impurity) is insignificant. The diamond crystals which are grown from a mixture containing 0.0005-0.002 at % boron and have perfect quality and a lattice mechanism of scattering can be considered as a reference semiconductor.