Ellipsometry of Al₂O₃thin films deposited on Si and InP

Abstract

Al 2 O 3 thin films, possessing potential for MIS electronic applications, have been deposited on clean Si and InP surfaces by evaporating powder from a graphite cell heated by electron bombardment. The build up of the films was monitored by Auger electron spectroscopy (AES).Continuous, amorphous films were also prepared on microgrids, for TEM studies. The film thickness was measured using multiple angle of incidence (66-72 • ) and 70 • angle ellipsometry using a 633 nm laser line. Calibration curves have been calculated for n = 1.61-1.77 limits for Al 2 O 3 and various substrates. They were considerably affected by the substrate optical constants. Evaluation of ellipsometric data resulted in typical thickness values of 5-10 nm as confirmed with cross-sectional TEM.

Graded refraction index antireflection coatings based on silicon and titanium oxides

“…Incident angle is fixed at 70°. The classical ellipsometric method for in situ control consists of following the trajectory of the ellipsometric angles measured during the process [5,12].…”

“…Therefore, it is necessary to optimize the refraction index grading profile to get minimum reflectance. To realize these coatings, several materials (oxynitrites, hydrogenated nitrides, porous titanium oxide) deposited by using various processes (PECVD, sputtering techniques) were described in the literature [9][10][11][12]. Among the methods of deposition used, the plasma enhanced chemical vapor deposition using the electron cyclotron resonance (ECR-PECVD) allows to obtain materials with good dielectric properties deposited at low pressures and practically at the room temperature [5,11].…”

Characterizations of Al2O3/ZnO Grown on Si Substrate by Plasma Enhanced Atomic Layer Deposition

“…Al 2 O 3 and ZnO materials have been studied for many applications such as high-k gate dielectrics [1,2], insulators in III-V MIS structures [3], light emitting diodes, etc. due to their large bandgaps relative to SiO 2 , large conduction band offset to Si, and low leakage current [4].…”