Rapid and broad-range thickness estimation method of hexagonal boron nitride using Raman spectroscopy and optical microscope

Abstract

Hexagonal boron nitride (hBN) has drawn great attention for its versatile applications in electronics and photonics, and precise estimation of its thickness is critical in many situations. We propose a rapid and broad range (10–500 nm) in situ thickness estimation method for transparent hBN and SiO2 layers on the Si substrate using Raman peak intensity ratios at two wavenumbers and optical microscopy image analysis. We theoretically and experimentally demonstrate our method for a wide range of hBN layer thicknesses, and the estimated results show excellent agreement with the measured results with a percentile estimation error of 2.5%.