Novel in situ Spectroscopic Ellipsometer for Real Time Analysis of CVD Diamond Films
Abstract
A split reflected beam spectroscopic ellipsometer (SRBSE) was designed assembled and used to perform elliposmetric measurements on four different samples. The four samples were: (1) a base silicon wafer, (2) a silicon wafer coated with diamond-like carbon, (3) a silicon wafer coated with diamond of 70% of its surface area, and (4) a silicon wafer coated with a fully dense diamond film. The purpose of the program was to determine whether SRBSE could distinguish between different carbon films deposited on silicon substrates, thereby serving as a low cost alternative to more expensive spectroscopic techniques. The SRBSE could not provide accurate ellipsometric results over the range of light wavelengths investigated. The SRBSE could distinguish a coated substrate from an incoated substrate. The measurements were too inaccurate to distinguish between the various types of carbon coatings on silicon. The lack of accuracy was attributed to sensitivity of SRBSE to slight changes in optical beam alignment, polarization, and monochromaticity of the incident beam. Two important conclusions were drawn. 1. The required hardware configuration of a SRBSE instrument is dependent upon the type of sample being examined. The shape of the pyramidal beam splitter is dictated by the optical properties of the substate upon which films are deposited and, to a lesser extent, the optical properties of the films themselves. 2. A major reason for measurement error was the insufficiently strong beam intensities despite the fact all measurements were made under carefully controlled conditions designed to maximize the sensitivity of light detection. (JHD)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 04, 1989
- Accession Number
- ADA213218
Entities
People
- Richard J. Koba