Electronic properties of homoepitaxial (111) highly boron-doped diamond films

Abstract

The use of diamond as a semiconductor for the realization of transistor structures, which can operate at high temperatures (>700 K), is of increasing interest. In terms of bipolar devices, the growth of n-type phosphorus doped diamond is more efficient on the (111) growth plane; p-type boron-doped diamond growth has been most usually grown in the (100) direction and, hence, this study into the electronic properties, at high temperatures, of boron-doped diamond (111) homoepitaxial layers. It is shown that highly doped layers (hole carrier concentrations as high as 2×1020 cm−3) can be produced without promoting the onset of (unwanted) hopping conduction. The persistence of valance-band conduction in these films enables relatively high mobility values to be measured (∼20 cm2/V s) and, intriguingly, these values are not significantly reduced at high temperatures. The layers also display very low compensation levels, a fact that may explain the high mobility values since compensation is required for hopping conduction. The results are discussed in terms of the potential of these types of layers for use with high temperature compatible diamond transistors.

Intrinsic granularity in nanocrystalline boron-doped diamond films measured by scanning tunneling microscopy

“…Furthermore, the material rigidity and electrochemical robustness make it of interest for high-temperature electronic application such as diamond transistors 2 that could operate at T Ͼ 700 K. Besides of its potential technological applications, the fundamental properties of diamond constitute by themselves intriguing and fascinating research topics. For example, the evolution of the transport behavior on the boron dopant concentration might help understanding more general aspects such as the metal-insulator transition and its correlation with the appearance of a superconducting state.…”

Growth and electrical characterisation of δ-doped boron layers on (111) diamond surfaces

“…This suggests a metallic-like nature, which is expected for heavily doped layers. 3,16 Increasing the temperature of the samples results in the impedance of the samples reducing in a logarithmic relationship, as expected for thermally activated carriers, and by applying linear fits to the log of impedance versus reciprocal temperature, the gradient of the slope has been used to determine the activation energy of the conductive channels. Arrhenius plots of the B & D in Fig.…”

“…In the current study the (111) plane is proposed for d-layer deposition. The authors have previously shown that the (111) diamond plane can support higher doping densities for a given mobility value than diamond (100), 16 and the (111) diamond plane has also been found to be advantageous for the realization of superconductivity in diamond; 17 similar advantages may be useful in diamond d-doping. Firstly, the (111) crystal plane has an eight times higher boron incorporation density than the (100) diamond lattice plane, 18 which could allow for thinner d-layers with equivalent boron content.…”

Negative magnetoresistance in boron-doped nanocrystalline diamond films

“…Due to its outstanding electronic, mechanical, and thermal properties, diamond became a potential candidate for developing electronic devices which could meet the increasing demand 1 for smallness, higher performance, less power consumption, and heat dissipation. Furthermore, the material rigidity and electrochemical robustness are of interest for high temperature electronic application such as diamond transistors 2 that could operate at T Ͼ 700 K. In addition, diamond has also shown to have a wide branch of technological applications in optics, tribology, acoustics, and biology. For more details, the reader is referred to Williams et al 3 Recently, the observation of a negative magnetoresistance ͑NMR͒ regime in highly nitrogen-doped ͑n-type͒ ultrananocrystallite-diamond ͑UNCD͒ films has been reported.…”