A study of 1/f noise in aluminum, aluminum alloys and copper films.
Item
-
Title
-
A study of 1/f noise in aluminum, aluminum alloys and copper films.
-
Identifier
-
AAI9924817
-
identifier
-
9924817
-
Creator
-
Hayakawa, Satoshi.
-
Contributor
-
Advisers: Kelvin G. Lynn | Leonard O. Roellig | Martin Kramer
-
Date
-
1999
-
Language
-
English
-
Publisher
-
City University of New York.
-
Subject
-
Physics, Condensed Matter | Engineering, Materials Science
-
Abstract
-
The 1/f noise measurement reveals information on dynamical atomic kinetics in solids. Based on a successful development of a highly sensitive noise measurement system, we have studied the 1/f noise in Al, Al alloys and Cu films at the temperature from 11 to 450 K. In Al films, single crystal and bamboo grained films exhibited substantially smaller noise than polycrystalline films at room temperature. This is clear evidence that grain boundaries are responsible for the 1/f noise generation in polycrystalline films. Despite the difference of the noise magnitude, the temperature dependence of all Al samples showed a quite similar behavior at the temperature from 150 to 294 K. The normalized noise magnitude (Hooge Parameter alphaH) began to increase about 200 K. This temperature corresponds to an activation energy about 0.5 eV. It is related to a vacancy migration process. In polycrystalline films, this can be specified as grain boundary electromigration. It is known that adding Cu atoms to Al reduces electromigration. Such an effect was observed in Cu doped polycrystalline Al films. For temperatures < 150K, alphaH showed no particular structure in polycrystalline Al. However, in single crystal films, it was found that alphaH increased with decreasing temperature. A peak around 35K was found in single crystal, bamboo structure, and polycrystalline Al with 2% wt. Cu (Al-Cu(2%)) samples. The peak temperature is nearly equal in all the samples. This indicates the origin of peaks may be identical. The peak height reveals the cleaner samples showed the higher noise peaks. This counter intuitive result may indicate that the alpha H peaks are not attributable to simple thermally activated kinetics. Such a peak was also found in Cu films at about 70 K. Two types of explanation may be plausible. First, this may be due to the complicated dislocation dynamics. The low activation energy removes most of migration species in metals. Only, some dislocation kinetics can be activated. Second, a quantum interference effect, universal conductance fluctuation (UCF), was considered. A small metallic sample can be extremely sensitive to the repositioning of an impurity atom or a defect.
-
Type
-
dissertation
-
Source
-
PQT Legacy CUNY.xlsx
-
degree
-
Ph.D.
