Evaluation of stress in (111) homoepitaxial CVD diamond films by Raman spectrum and nitrogen-vacancy centers

Abstract The reduction of inhomogeneous stress in diamonds is crucially important for extracting excellent performance of semiconducting diamonds. In this study, to investigate elastic deformation in nitrogen doped (111) diamond films caused by stress, we evaluated the stress in these films using confocal Raman microscopy. The stress was detectable when the misorientation angle ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>θ</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">mis</mml:mi> </mml:mrow> </mml:msub> </mml:math> ) was below 3.7° and it decreased as <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>θ</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">mis</mml:mi> </mml:mrow> </mml:msub> </mml:math> increased. The Raman spectroscopic measurements, considered together with reported stress measurements by nitrogen-vacancy centers, suggest that the diamond film at low <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>θ</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">mis</mml:mi> </mml:mrow> </mml:msub> </mml:math> was subjected to compressive stresses that were stronger in the [111] direction than [ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>1</mml:mn> <mml:mover accent="true"> <mml:mrow> <mml:mn>1</mml:mn> </mml:mrow> <mml:mo>̅</mml:mo> </mml:mover> <mml:mn>0</mml:mn> </mml:math> ] or [ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover accent="true"> <mml:mrow> <mml:mn>1</mml:mn> </mml:mrow> <mml:mo>̅</mml:mo> </mml:mover> <mml:mover accent="true"> <mml:mrow> <mml:mn>1</mml:mn> </mml:mrow> <mml:mo>̅</mml:mo> </mml:mover> <mml:mn>2</mml:mn> </mml:math> ] directions.