Review on the thickness measurement of ultrathin oxide films by mutual calibration method

Abstract

Mutual calibration was suggested as a method to determine the absolute thickness of ultrathin oxide films. It was motivated from the large offset values in the reported thicknesses in the Consultative Committee for Amount of Substance (CCQM) pilot study P‐38 for the thickness measurement of SiO2 films on Si(100) and Si(111) substrates in 2004. Large offset values from 0.5 to 1.0 nm were reported in the thicknesses by ellipsometry, X‐ray reflectometry (XRR), medium‐energy ion scattering spectrometry (MEIS), Rutherford backscattering spectroscopy (RBS), nuclear reaction analysis (NRA), and transmission electron microscopy (TEM). However, the offset value for the thicknesses by X‐ray photoelectron spectroscopy (XPS) was close to zero (−0.013 nm). From these results, the mutual calibration method was reported for the thickness measurement of SiO2 films on Si(100) by combination of TEM and XPS. The mutual calibration method has been applied for the thickness measurements of hetero oxide films such as Al2O3 and HfO2. Recently, the effect of surface contamination was reported to be critical to the thickness measurement of HfO2 films by XPS. On the other hand, MEIS was proved to be a powerful zero offset method which is not affected by the surface contamination. As a result, the reference thicknesses in the CCQM pilot study P‐190 for the thickness measurement of HfO2 films on Si(100) substrate were determined by mutual calibration method from the average XRR data and MEIS analysis. Conclusively, the thicknesses of ultrathin oxide films can be traceably certified by mutual calibration method and most thickness measurement methods can be calibrated from the certified thicknesses.

Large-Area Thickness Measurement of Transparent Films Based on a Multichannel Spectral Interference Sensor

“…Ray radiation technology obtains the film thickness by detecting the attenuation of the ray intensity after penetrating the object. Despite that the ray radiation methods demonstrate the capacity for high-precision real-time film thickness measurement, the radioactive sources are expensive and highly hazardous [13][14][15]. Terahertz time-domain spectroscopy (THz-TDS) utilizes the time-of-flight (TOF) and resonance frequencies to acquire the thickness of the films.…”

Calculation of the Energy Spectrum of Quantum Particle in Double Potential Pit

“…Quantum properties and effects determine the unique physical characteristics of the so-called heterostructures, i.e., artificial periodic layered formations [22]. Usually, individual layers of heterostructures have the thickness of about nanometres [23].…”

Error Analysis for Repeatability Enhancement of a Dual-Rotation Mueller Matrix Ellipsometer

“…Benefiting from the characteristics such as high-precision, fast, non-contact, easy-to-integrate, ellipsometer has been used as a practical standard tool in the semiconductor industry [1,2], for optical properties measurements of thin films [3-5] and the thickness measurement of ultrathin oxide films [6]. Besides, there exists an increasing trend in the modern ellipsometry to deal with increasingly complex media such as biomedical specimens [7].…”