Surface behavior of heterosubstrates during BEN-MPCVD: a key for diamond heteroepitaxy
- PDF / 2,724,843 Bytes
- 11 Pages / 612 x 792 pts (letter) Page_size
- 46 Downloads / 135 Views
1039-P04-03
Surface behavior of heterosubstrates during BEN-MPCVD: a key for diamond heteroepitaxy Jean-Charles ARNAULT1, Samuel SAADA1, Sophie DELCLOS1, Luciana INTISO2, Stéphane PECORARO3, and Philippe BERGONZO1 1 Diamond Sensor Laboratory, CEA/Saclay, CEA-LIST, Gif sur Yvette, 91191, France 2 Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, Via della Ricerca Scientifica, Rome, Rome, 00133, Italy 3 IPCMS-GSI, UMR 7504, BP 43, 23, rue du Loess, Strasbourg, 67034, France ABSTRACT The chemical stability of three heterosubstrates (Si, 3C-SiC and iridium) has been studied using the same MPCVD reactor during the successive steps of BEN process. An in situ sequential approach allows a monitoring of the chemical modifications induced by interactions between plasma and surfaces. Contrary to silicon, 3C-SiC and iridium underwent weak surface evolutions during BEN. This leads to favourable conditions for the interface formation in agreement with the better Highly Oriented Diamond films reported in the literature. A short description of the nucleation pathways identified for each heterosubstrate is also presented. INTRODUCTION Diamond heteroepitaxy is a major challenge to grow in large scale diamond films devoted to active electronic or medical applications (hadrontherapy). Among the studied heterosubstrates, silicon has been widely considered because of its easier integration in the device technology. Jiang et al. [1] reported Highly Oriented Diamond (HOD) film on silicon. Then, higher crystalline qualities have been achieved on 3C-SiC [2] and iridium [3] substrates. In addition to well-matched crystalline parameters, the ideal heterosubstrate must demonstrate an excellent thermal stability and a low difference of thermal expansion coefficients. These parameters are gathered in the Table 1 for silicon, cubic-silicon carbide and iridium heterosubstrates. In addition, the specific interaction of a given heterosubstrate with carbon species produced by the CVD microwave plasma has to be considered. Indeed, it is strongly involved in the interface formation which is essential to insure heteroepitaxy. Among studied heterosubstrates, very different behaviors have been observed such as etching by atomic hydrogen, carbide formation, carbon dissolution into the substrate or graphite formation. These competing mechanisms taking place during diamond nucleation could have detrimental consequences on the quality of the diamond/substrate interface. Finally, the integration of the heterosubstrate in device technology has to be considered. The main topic of this paper is to investigate the interactions of the CVD microwave plasma with the different heterosubstrate surfaces during the BEN process. Then, the consequences on the nucleation mechanism of diamond and on the interface formation are described. These three heterosubstrates have been studied using the same MPCVD reactor connected to a UHV system allowing surface analysis. A short review concerning nucleation mechanisms has been added for each heterosubst
Data Loading...
