Investigation of boron delta doped layer growth
Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, Russia
Attention to diamond as an electronic material is receiving international attention due to the improvements in the growth of synthetic diamond by both chemical vapor deposition (CVD) and high pressure high temperature (HPHT) techniques. Diamond offers significant advantages over other semiconductor materials due to its high electrical breakdown strength, high carrier mobilities, high thermal diffusivity, and other exceptional properties. Diamond semiconductor devices will likely impact applications in high power, high frequency, high temperature, and/or harsh or corrosive environments.
In this paper, the research results on the boron incorporation into the single-crystalline CVD diamond during the growth of the delta-doped layers are presented. Investigations were made on a new type of CVD reactor designed for growth of delta layers inside the diamond . The reactor consists of a cylindrical cavity resonator with a quartz tube placed inside, in which laminar gas flow without vortex is maintained. The plasma is created in the reactor by the magnetron with 2.45 GHz frequency. Main features of the new type reactor are the following: (a) use of fast switching of feed gases flow, (b) reactor design, allowing creation of a laminar flow of gases. This approach allowed us to obtain heavily boron doped thin layers and to implement two-dimensional hole "gas" in diamond with high mobility and hole concentrations. Boron concentration in the delta layer and the doping profile was determined by SIMS method. As the result of experiments we found the optimal diamond deposition regime which allows to obtain doped delta layers with thickness of 1 - 2 nm with concentrations of boron greater than 1020 cm-3. Such thin doped layers are highly desirable for the development of diamond-based field-effect transistor and other next generation electronic devices.
 A. L. Vikharev, A. M. Gorbachev, M. A. Lobaev, et. al, Phys. Status Solidi RRL, 1–4 (2016) 016) / DOI 10.1002/pssr.201510453