Analysis of boron in CVD diamond surfaces using neutron depth profiling

Abstract

Neutron depth profiling (NDP) is a method of near surface analysis for isotopes that undergo neutron-induced positive Q-value charged particle reactions, e.g., (n,alpha), (n,p). Because of its large cross section and large Q-value, the 10B(n,α) 7Li reaction has been widely employed for NDP studies. We have used the NDP technique to study the concentration and distribution of boron in CVD diamond layers. The measurements were made using the new Cold Neutron Depth Profiling instrument at the NIST Cold Neutron Research Facility. The diamond samples were prepared at the Materials Research Laboratory at the Pennsylvania State University. The doped diamond single crystal films were grown by microwave plasma chemical vapor deposition from a mixture of methane, hydrogen and diborane. Natural type IIa crystals cut along the (001) plane were used as substrates. Results of the measurements are presented.