Electron-Beam-Induced Dissociation of Boron-Deuterium Pairs in Diamond
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0956-J04-04
Electron-Beam-Induced Dissociation of Boron-Deuterium Pairs in Diamond Julien Barjon1, Jacques Chevallier1, François Jomard1, Céline Baron2, and Alain Deneuville2 1 Groupe d'Etude de la Matière Condensée (GEMaC), Université de Versailles Saint-Quentin-enYvelines, CNRS, 1 place A. Briand, Meudon, 92195, France 2 Laboratoire d’Etudes des Propriétés Electroniques des Solides (LEPES), CNRS, BP 166, Grenoble, 38042, France
ABSTRACT The diffusion of deuterium in boron-doped homoepitaxial diamond films leads to the passivation of boron acceptors via the formation of B-D pairs. In this letter, the stability of these complexes is investigated under the stress of a low-energy (10keV) electron-beam irradiation at low temperature (~100K). The dissociation of the complexes is evidenced by cathodoluminescence spectroscopy and is shown to result in the reactivation of most acceptors. The dissociation yield per incident electron is found to be strongly dependent on the e-beam current, which suggests a dissociation involving a vibrational excitation of the complexes by hot electrons. INTRODUCTION In many semiconductors, the presence of hydrogen is known to passivate impurities and defects via the formation of hydrogen-related complexes. These properties of hydrogen - and deuterium, its isotope – have been successfully used to improve the performance of electronic devices. In the case of metal-oxyde-semiconductor structures operating under hot electron injection, the hydrogenation of the oxide-semiconductor interface, SiOx-Si, passivates dangling bonds, extending the structure life-time [1]. In polycrystalline solar cells, hydrogenation of the device passivates recombining grain boundaries increasing the device energy conversion efficiency, as well as panel yields [2]. In InP optical waveguides hydrogenation reduces propagation losses due to free carriers absorption, passivating Zn acceptors [3]. It has been well established that the physical properties of diamond makes of it an extremely interesting semiconductor for high temperature, high power and high frequency electronic devices. The recent progresses of plasma assisted chemical vapor deposition (CVD) for growing epitaxial diamond bring the possibility of making such devices almost at hand. It has been shown recently that the diffusion of deuterium (also called deuteration) in p-type diamond doped with boron is efficient and results in the passivation of boron acceptors by the formation of B-D complexes [4]. If a second deuteration is performed some deuterium excess occurs which can lead to n-type diamond [5]. To evaluate the potential of the deuteration (or hydrogenation) process to passivate dopants in diamond-based devices, the stability of the B-D pairs remains to be studied under different stresses. In this work, we focus on the simple passivation case, where each boron acceptor is passivated by forming a pair with a single deuterium atom. We investigate the stability of these pairs under the hot electrons produced by a low-energy electron-beam-irradiation (LE
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