The effect of boron doping and gamma irradiation on the structure and properties of microwave chemical vapor deposited boron-doped diamond films

Abstract

We investigated the effects of gamma irradiation doses of 50, 100, and 103 kGy on boron-doped diamond (BDD) thin films synthesized using microwave plasma-assisted chemical vapor deposition with varying boron concentrations of [B]/[C]gas = 100, 1000, 2000, and 4000 ppm. The diamond thin films were characterized prior to and post-irradiation and the influence was assessed in terms of morphology, structure, and physical properties using scanning electron microscopy, atomic force microscopy, x-ray diffraction, vibrational spectroscopy (Raman and IR), x-ray photoelectron spectroscopy, and electrical measurement techniques. The results clearly showed that the response of gamma irradiation on BDD films was distinctive compared to those of undoped diamond films with changes in electronic behavior from metallic (>1019 to 1020 cm–3) to semiconducting (≤1019 cm–3), especially in the case of heavily boron-doped diamond films demonstrated by micro-Raman spectroscopy and electrical property characteristics. In fact, this modification in electrical property behavior induced by “gamma conditioning” can be effectively used to fine control boron doping in chemically vapor deposited diamond much needed for various electronic devices. The “gamma conditioning” refers to material processing by radiation which helps to passivate electrically active boron and defects with hydrogen migration thus fine tunes the boron acceptor concentration albeit that this is difficult to achieve during BDD film deposition. In addition, the results also indicate that almost all of the BDD films studied hereby tend to reach a state of damage saturation when submitted to gamma irradiation of 103 kGy. We discuss our novel findings in terms of the interplay of boron-hydrogen in diamond with possible multiple scenarios: (i) the generation of point/Frenkel defects due to Compton scattered electrons, (ii) the formation of a nonmetallic boron-rich borocarbide (e.g., B13C2) phase, (iii) the passivation of electrically active acceptor (B) sites due to the invariable presence of H in the grains and at the grain boundaries, (iv) the desorption of H from the diamond surface, and (v) the “priming or pumping” effect, which improves the electronic properties by compensating for the shallow boron acceptors to produce semiconducting/insulating material, verified by the cold neutron depth profiling technique.

Calculation of the Electronic Parameters of an Al/DNA/p-Si Schottky Barrier Diode Influenced by Alpha Radiation

“…The increase may be attributed to the decrease in free carrier concentration and charge mobility. Higher barrier height values denote lower reverse currents [ 28 ]. Furthermore, the hypersensitivity phenomenon was responsible for the increase in the Φ and R S values.…”

“…Furthermore barrier height values were observed to increase after 6, 10, 20 and 30 min of radiation, except for 4 and 40 min, which registered a decrease of about 0.68 eV. The electrical resistance increase may be due to drop in the forward current at high voltages whereas the drop in barrier height values is as a result of the growth of the reverse current [ 28 ]. Hypersensitivity of DNA to radiation is thought to be responsible for changes in the ideality factors and series resistance.…”

The effect of the electron irradiation on the series resistance of Au/Ni/6H-SiC and Au/Ni/4H-SiC Schottky contacts

“…Increase of the barrier height is mainly responsible for the decrease of the reverse current. An increase in series resistance indicates that the reason is either products of the mobility and the free carrier concentration have reduced or the compensation of doping in the semiconductor [20]. The former case can be explained by the introduction of irradiation induced defect centers.…”

Nano-structure and property transformations of carbon systems under γ-ray irradiation: a review

“…Diamond is renowned among scientists and technologists for its impressive combination of exceptional physical (mechanical, thermal, electrical, electrochemical, and biological) properties offering multifunctionality that qualifies it to become the 21st century engineering material for multiple applications. 54,55 Diamond has a reputation for being radiation-hard material, therefore it is being suggested as a suitable semiconductor for detectors in high irradiation environments. [56][57][58]…”