Single Crystal CVD Diamond Growth and Characterizations

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0956-J07-02

Single Crystal CVD Diamond Growth and Characterizations Nicolas Olivier Tranchant1, Dominique Tromson1, Zdenek Remes2, Licinio Rocha1, Milos Nesladek1, and Philippe Bergonzo1 1 DRT/LIST/DETECS/SSTM, CEA SAclay, CEA Saclay, DRT/LIST/DETECS/SSTM/LTD, Bât 451, pce 74, Gif-Sur-Yvette, Gif-Sur-Yvette, 91400, France 2 Institute of Physics, Academy of Sciences of the Czech Republic, Praha, Croatia Abstract Due to its radiation hardness, single crystal CVD diamond is a remarkable material for the construction of detectors used in hadron physics and for medical therapy. In this work, single crystal CVD diamond plates were grown in a microwave plasma reactor, using home design substrate holder and a relatively high pressure. Optical Emission Spectroscopy was employed during the MW-PECVD growth to characterize excited species present in the plasma and to detect the presence of residual gases such as nitrogen which is unsuitable for detector’s applications. The samples were characterized using various methods such as Raman spectroscopy, photoluminescence (PL), photocurrent spectroscopy, Raman mapping, birefringence microscopy, optical microscopy and also AFM. The best sample, exhibits a FWHM for the 1332 cm-1 Raman peak about 1.6 cm-1. Room temperature PL spectra showed no N–related luminescence, confirming the high quality of the grown single crystal diamond.

1. Introduction Diamond is a material with a high radiation hardness which makes it a good candidate for detectors and namely towards hadron physics applications. It combines a unique set of properties and especially a wide band gap, a high electronic mobility and a fast response time. The advantages of single crystal diamond as compared with polycrystalline material are a higher mobility and also a significantly lower density of electrically active traps and recombination centers [1]. The aim of this study is to investigate the structural, optical and electronic properties of single crystal diamonds grown by microwave plasma enhanced chemical vapor deposition (MWPECVD) at CEA-LIST in Saclay.

2. Experimental details Our samples were grown in an AX5400 ASTEX reactor, with a base pressure of 10mBar, on commercial HPHT single crystal substrates oriented (100), using from 2 to 10% methane-in-hydrogen mixtures. During the growth the optical emission spectroscopy (OES) was probed in the optical range of 350 to 1000nm using an USB Fiber Optic Spectrometer. Before each deposition, the substrate was oxidized in a hot mixture of H2S04 and KNO3 during 30 minutes to remove all surface impurities. After this chemical treatment substrates were rinsed in an ultrasonic bath in deionised water. 7

Additional substrate surface treatment was performed inside the CVD reactor by plasma etching using 4% oxygen in hydrogen plasma with MW power of 1000W. The set up was optimized in order to have the surface as smooth as possible before the deposition [2]. After deposition, the CVD diamond plate was removed from the substrate by laser cutting. After separation from the HPHT substr

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