AVS 47th International Symposium
    Thin Films Wednesday Sessions
       Session TF+EL-WeA

Paper TF+EL-WeA7
Characterization of the Phase Evolution of Boron Nitride Thin Films using Real Time Multichannel Ellipsometry from 1.5 to 6.5 eV

Wednesday, October 4, 2000, 4:00 pm, Room 203

Session: In-situ Characterization of Thin Film Growth
Presenter: J.A. Zapien, The Pennsylvania State University
Authors: J.A. Zapien, The Pennsylvania State University
R. Messier, The Pennsylvania State University
R.W. Collins, The Pennsylvania State University
Correspondent: Click to Email
Cubic boron nitride (cBN) is the second hardest material after diamond. This property together with its superior chemical and thermal stability makes it a very promising candidate for hard coating applications. The layered structure of cBN films on crystalline silicon (c-Si) substrates is well documented. It is commonly accepted that a sequence of amorphous and hexagonal (hBN) layers grow prior to cBN nucleation. This sequence has been described by real time measurements including polarized infrared reflectance (PIRR) spectroscopy, and infrared spectroscopic ellipsometry (IRSE). The demand for real time characterization techniques is motivated by the use of complex deposition sequences used to optimize film characteristics. Recently, we have developed a rotating polarizer multichannel ellipsometer with spectral capabilities that extend well into the uv range. With this instrument, 132 spectral points in the ellipsometric parameters (@psi@, @DELTA@) covering the photon energy range from 1.5 to 6.5 eV can be collected with a minimum acquisition time of 24.5 ms, while maintaining sub-monolayer sensitivity. As a result of the uv-extended capabilities, the new multichannel ellipsometer is well suited to study wide band gap materials in real time during preparation. Here we report the use of the uv-extended multichannel ellipsometer to study the growth and layered structure of cBN films deposited on c-Si using two processes: i) rf magnetron sputtering of a BN target with pulsed dc substrate bias, and ii) pulsed dc sputtering of a B@sub 4@C target with rf substrate bias. The phase evolution of the BN films based on the optical response in the visible-uv spectral region has been found to be in good agreement with ex-situ Fourier Transform Infrared Spectroscopy (FTIR) performed at the end of the deposition. The effect of the deposition conditions on the phase evolution and optical properties of the films will be presented.