Accession Number : ADA187575

Title :   The Soft/Hard Wet Anodization of Aluminum Oxide and Its Use in a Thin Film Multilayered Capacitor.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH

Personal Author(s) : Dickey, John R

PDF Url : ADA187575

Report Date : Jan 1986

Pagination or Media Count : 152

Abstract : LIterature has identified and characterized the existence of barrier and porous alumina formed by the electrolytic anodization of aluminum. Barrier films are limited in thickness by the formation voltage, found to be typically 12 to 15 A/volt. Porous layers may be formed thicker without such limitation. In this work, anodization was performed on vacuum or sputter deposited aluminum films typical of those used for interconnect metal for integrated circuits. Substrates were thermally oxidized silicon wafers. The anodization consisted of a two step operation. A layer of soft anodized consisted of a two step operation. A layer of soft anodized aluminum was first formed using sulfuric acid electrolyte. This anodized layer was then subjected to a boric acid hard anodization. Single level and multilevel capacitor structures were formed and dielectric evaluation performed. Effective dielectric contents of up to approximately 70, volume resistivities of up to 1.2x10 to the 18th power ohm-cm and breakdown voltages of up to 2.38 times that of the hard anodization forming voltage were observed. Cleaved SEM cross sections were examined and indicated a dense amorphous alumina layer was formed. This is in agreement with reported observations that amorphous alumina has better dielectric properties than crystalline layers.

Descriptors :   *ALUMINUM OXIDES, *AMORPHOUS MATERIALS, *ANODIC COATINGS, *BORIC ACID, *ELECTROLYSIS, *INTEGRATED CIRCUITS, *SUBSTRATES, ALUMINUM, BARRIER COATINGS, CAPACITORS, CROSS SECTIONS, CRYSTALS, DENSITY, DEPOSITION, DIELECTRIC PROPERTIES, DIELECTRICS, ELECTRICAL RESISTANCE, ELECTROLYTES, FILMS, HEAT, LAYERS, OPERATION, OXIDATION, POROUS MATERIALS, SILICON, SPUTTERING, STRUCTURES, SULFURIC ACID, TEST AND EVALUATION, THICKNESS, THIN FILMS, VACUUM, VOLTAGE, VOLUME, WAFERS, THESES

Subject Categories : Physical Chemistry
      Coatings, Colorants and Finishes
      Laminates and Composite Materials
      Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE