Award Date

1-1-2008

Degree Type

Thesis

Degree Name

Master of Electrical Engineering (MEE)

Department

Electrical and Computer Engineering

First Committee Member

Rama Venkat

Second Committee Member

Ravhi S. Kumar

Number of Pages

62

Abstract

Phase change alloys have recently gained increasing attention due to their application in developing phase change random memory (PRAM) devices, as Flash memory based devices are rapidly approaching their technological limitations. The most dominant features of PRAM devices are its non-volatile nature, compatible with present day IC's manufacturing process, high density, fast operation, low power consumption etc; Devices built on binary alloys such as Antimony - Selenium (SbSe) exhibit certain superior properties such as fast operation, reduced power consumption, economical etc. compared to that of ternary alloy (GST). In order to understand this behavior in detail, bulk SbxSe 100-x (40 ≤ x ≤ 70) alloys are synthesized and deposited as thin films on silicon (100) plane substrate. Series of experiments such as X-ray diffraction analysis (XRD), Energy dispersive X-ray diffraction (EDAX), Spectroscopic Ellipsometer, Hall test experiments are carried out to characterize both the bulk and thin films. EDAX experiments show the deviation between bulk and thin films compositions is less than 10%. Diffraction patterns of bulk exhibit orthorhombic structure, i.e., Sb2Se3 type where as thin films demonstrate amorphous behavior. Impact of annealing on thin films is studied by heating the films to 170°C under argon (Ar) ambience. Post annealing results of Sb40Se60 thin films show the crystal structure is orthorhombic and crystallization temperature (Tc) increases with increase in Sb content of the compound. Ellipsometry and Hall measurements of annealed films exhibit high refractive index (n), low extinction coefficient (k) and high carrier concentration with associated low carrier mobility. Further the conductivity of annealed Sb40Se60 thin films switches from p to n type.

Keywords

Alloys; Antimony; Bulk; Change; Characterization; Film; Phase; Sb; Selenium; Synthesis; Thin

Controlled Subject

Electrical engineering; Optics; Materials science

File Format

pdf

File Size

1331.2 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

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