OPTICAL FUNCTIONS OF DISCONTINUOUS ALUMINUM FILMS - INTRABAND AND INTERBAND CONTRIBUTIONS TO PARTICLE RESONANCE-ABSORPTION

被引:8
作者
NGUYEN, HV [1 ]
COLLINS, RW [1 ]
机构
[1] PENN STATE UNIV,DEPT PHYS,UNIV PK,PA 16802
来源
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION | 1993年 / 10卷 / 03期
关键词
D O I
10.1364/JOSAA.10.000515
中图分类号
O43 [光学];
学科分类号
070207 ; 0803 ;
摘要
We have developed a comprehensive optical model that accounts for the continuous evolution of the effective optical functions of discontinuous Al (particle) films in the vicinity of the resonance absorption feature as a function of the particle size. We obtain unprecedented agreement between the calculated and experimental results for both real and imaginary parts of the effective dielectric functions of particle films that are from 1 to 6 nm in thickness. The experimental studies rely on a unique rapid-scanning multichannel ellipsometer to collect (psi, DELTA) spectra from 1.3 to 4.0 eV during Al particle-film growth by evaporation and sputtering onto SiO2/c-Si substrates. In a least-squares regression analysis the effective dielectric functions that we obtained experimentally are fitted to a generalized Maxwell-Garnett effective-medium theory with three free parameters. Two parameters describe the particle-film morphology. The third parameter is the mean free path, which we assume to be common to electrons that participate in both intraband and interband transitions. From the modeling we find that the optical functions of the particles themselves are remarkably independent of size and shape as well as of the method of preparation. This is presumably because scattering at defects that are internal to the particles determines the electron relaxation time. The simplifying assumption regarding particle-film morphology (i.e., identical spheroids) does not appear to compromise these conclusions. From the overall study we conclude that the crystalline quality of substrate-supported metallic particles as small as 0.5 nm in radius can be assessed solely from noninvasive real-time spectroscopic ellipsometry measurements.
引用
收藏
页码:515 / 523
页数:9
相关论文
共 39 条
[1]   WAVE-FORM ANALYSIS WITH OPTICAL MULTICHANNEL DETECTORS - APPLICATIONS FOR RAPID-SCAN SPECTROSCOPIC ELLIPSOMETRY [J].
AN, I ;
COLLINS, RW .
REVIEW OF SCIENTIFIC INSTRUMENTS, 1991, 62 (08) :1904-1911
[2]   MORPHOLOGY AND SIZE DISTRIBUTIONS OF ISLANDS IN DISCONTINUOUS FILMS [J].
ANDERSSON, T ;
GRANQVIST, CG .
JOURNAL OF APPLIED PHYSICS, 1977, 48 (04) :1673-1679
[3]   UNAMBIGUOUS DETERMINATION OF THICKNESS AND DIELECTRIC FUNCTION OF THIN-FILMS BY SPECTROSCOPIC ELLIPSOMETRY [J].
ARWIN, H ;
ASPNES, DE .
THIN SOLID FILMS, 1984, 113 (02) :101-113
[4]   INTERBAND ABSORPTION AND OPTICAL PROPERTIES OF POLYVALENT METALS [J].
ASHCROFT, NW ;
STURM, K .
PHYSICAL REVIEW B, 1971, 3 (06) :1898-&
[5]  
Aspnes D. E., 1981, Proceedings of the Society of Photo-Optical Instrumentation Engineers, V276, P188
[6]   STATISTICAL-THEORY OF DIELECTRIC PROPERTIES OF THIN ISLAND FILMS .1. SURFACE MATERIAL COEFFICIENTS [J].
BEDEAUX, D ;
VLIEGER, J .
PHYSICA, 1974, 73 (02) :287-311
[7]   SOLID-PHASE REDUCTION OF SIO2 IN THE PRESENCE OF AN AL LAYER [J].
BLATTNER, RJ ;
BRAUNDMEIER, AJ .
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY, 1982, 20 (03) :320-323
[8]   GENERALIZED MAXWELL GARNETT EQUATIONS FOR ROUGH SURFACES [J].
CHAN, EC ;
MARTON, JP .
JOURNAL OF APPLIED PHYSICS, 1974, 45 (11) :5004-5007
[9]   REAL-TIME SPECTROSCOPIC ELLIPSOMETRY FOR CHARACTERIZATION OF THIN-FILM OPTICAL-PROPERTIES AND MICROSTRUCTURAL EVOLUTION [J].
COLLINS, RW ;
AN, I ;
NGUYEN, HV ;
GU, T .
THIN SOLID FILMS, 1991, 206 (1-2) :374-380
[10]   Interpretation of the anomalies of the optical constants of thin metal layers. [J].
David, Erwin .
ZEITSCHRIFT FUR PHYSIK, 1939, 114 (7-8) :389-406