AFM and XPS studies of a homoepitaxial diamond (001) surface nitrided using 500-eV N2+ ion beam

Abstract A homoepitaxially grown p-type diamond (001) surface was nitrided by irradiation with a 500-eV N 2 + ion beam. X-Ray photoelectron spectra (XPS) were taken in situ during the nitridation. The C1s and N1s XPS spectra were divided into three (A, ∼284.7; B, ∼285.6; and C, ∼287.3 eV) and four (D, ∼398.4; E, ∼399.5; F, ∼401.0; and G, ∼403.3 eV) components, respectively. The A component of the C1s core level originated from the diamond substrate lying under the nitrogen penetration zone. The B and C components came from the nitrogen-diluted layer and from the carbon nitrides, respectively. The composition ratio of nitrogen/carbon in the C phase, N D+F /C C , was 0.71. The N all /C B+C ratio was 0.25. The morphology of the surface was also measured in air by atomic force microscope (AFM). It was found that grain-like material covered the surface after nitridation. A typical grain size was approximately 50 nm in diameter with a height of 5 nm. However, the grains themselves were not carbon nitrides. The crystallinity of the nitride was investigated using reflection high-energy electron diffraction (RHEED), but the formation of β-C 3 N 4 could not be confirmed from the RHEED patterns, due to overlapping with the twin structures of diamond.