In situ etching-back processes for a sharper top interface in boron delta-doped diamond structures

• Published in: Diamond and related materials Vol. 24; pp. 175 - 178
• Main Authors: Fiori, Alexandre, Tran Thi, Thu Nhi, Chicot, Gauthier, Jomard, François, Omnès, Franck, Gheeraert, Etienne, Bustarret, Etienne
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2012; Elsevier
• Subjects: Boron; Chemical and Process Engineering; Cross-disciplinary physics: materials science; rheology; Delta-doping; Diamond; Dry etch; Engineering Sciences; Etching; Etching and cleaning; Exact sciences and technology; Fullerenes and related materials; diamonds, graphite; Materials science; Microwave plasmas; Multilayers; Optimization; Physics; Physics of gases, plasmas and electric discharges; Physics of plasmas and electric discharges; Plasma applications; Profiling; Secondary ion mass spectrometry; SIMS; Specific materials; Switching; Diamond; Delta-doping; Dry etch; SIMS; Epitaxial layers; Multilayer; Diamonds; Doping; Doped materials; Secondary ion mass spectrometry; Diamond structure; Switching; Interfaces; Multilayers; Boron; Plasma etching; Boron additions; Microwave discharge
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2012.01.018

One of the main challenges of delta-doping of diamond with boron resides in minimizing the width and optimizing the structural quality of the interface region between the heavily-doped ultra-thin layer and the non intentionally doped high mobility epilayers. In this work, we present an in situ etching-back approach to this problem. In particular, a careful SIMS profiling of the top interface shows that advanced gas switching procedures and adequate in situ O2 and H2 plasma etch steps lead to a rising depth lower than 2nm per decade over 3 to 4 orders of magnitude of boron concentration. A specificity of the present work is that the multilayer structures were obtained without interrupting the microwave plasma during the whole process. ► Challenge of delta-doping of diamond is in reducing width and optimizing interfaces. ► Smart gas switching and in situ O2 and H2 plasma steps make sharp and thin interfaces. ► Multilayer structures were grown without plasma interruption during the process.