Optical Properties of Wide Band Gap Semiconductor by Spectroscopic Ellipsometry and Simulation
Date Issued
2007
Date
2007
Author(s)
Huang, Chu-Wan
DOI
en-US
Abstract
Spectroscopic ellipsometry (SE) is an optical measurement of the polarization change occurring when light interacts with materials. Model-based regression is limited to the information content available from the experimental data. For this reason, ellipsometry is often performed at multiple angles and wavelengths to increase the available information. SE measurements provide additional information for each new wavelength. The optical constant dispersion carries information about many material properties. SE characterization has been applied to a wide range of industrial and research applications. Traditional SE from UV-VIS to NIR can characterize the films and stacks used with any of these device applications. SE has been established to be a very effective technique for the characterization of thin surface layers with high sensitivity and accuracy. Variable angle spectroscopic ellipsometry (VASE) is important for metrology in several industries, and is a powerful technique for research on new materials and processes.
In this thesis, we report the dielectric constants of different semiconductors. Silicon based optoelectronics integration offers promising opportunity for low-cost solutions to optical communications and interconnects. The design of optoelectronic devices fabricated from III-nitride materials is aided by knowledge of the refractive index and absorption coefficient of these materials. The optical properties of GaN, AlN and AlGaN grown on sapphire substrates were investigated by means of transmittance and reflectance measurements. These properties provide information critical to the optimal design of solar blind detectors or other optoelectronic devices.
ZnO is an attractive material for many applications in optics and optoelectronics. For instance, since a room temperature lasing has been observed in ZnO thin films, the epitaxial ZnO is a promising candidate material for ultraviolet lasers.
High-K metal-oxide dielectrics have recently been the focus of substantial ongoing efforts directed towards finding a replacement for SiO2 as the gate dielectric in complementary metal-oxide-semiconductor devices. HfO2, ZrO2, and their SiO2 mixtures show promise for this purpose. The integration of chemical vapor deposited organo-silicate glass (OSG) interlayer dielectrics (ILD) has challenged the IC industry to formulate new methods of metrology and characterization.
6H–SiC are excellent substrates for the synthesis of AlGaN–GaN heterojunction field effect transistors. Unfortunately, the quality of GaN layers grown on SiC is inferior to that grown on the commonly used sapphire substrate due to the relative poor surface properties of SiC. However, preparing such surfaces is relatively difficult.
The lead zirconate titanate thin-film system Pb(ZrxTi1-x)O3 (PZT) is one of the most attractive perovskite materials for microstructured ferroelectric devices. The thin film synthesis of PZT is the subject of widespread current interest as its unique properties offer many interesting device applications. Among these are microwave acoustic devices, infrared imagers, integrated optic circuits, optical display, and high performance semiconductor memories.
Subjects
橢偏儀
介電常數
氮化鎵
氧化鋅
氧化鉛鋯鈦
spectroscopic ellipsometry
dielectric constants
GaN
ZnO
PZT
Type
thesis
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