Date of Award

12-1-2021

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

College/School/Department

Department of Nanoscale Science and Engineering

Program

Nanoscale Sciences

Content Description

1 online resource (xvii, 114 pages) : illustrations (some color)

Dissertation/Thesis Chair

James R Lloyd

Committee Members

James R Lloyd, Vincent P LaBella, Hassaram Bakhru, Carl A Ventrice, Brian T McGowan

Keywords

Dielectric Breakdown, Dielectric Materials, Failure Analysis, Hyperfine interaction, Magnetoresistance, Materials Reliability, Dielectrics, Dielectric devices, Integrated circuits, Interconnects (Integrated circuit technology)

Subject Categories

Materials Science and Engineering | Nanoscience and Nanotechnology | Physics

Abstract

The introduction of low dielectric constant materials within the integrated circuit (IC) chip technology industry was a concerted effort to decrease the resistance-capacitance (RC) time delay inherent within the dielectric materials used as insulators. This stems from a demand for greater device density per IC chip and decreased feature sizes but is fast becoming a reliability issue. Concomitant with the demand for decreased feature sizes, also in adherence with Moore’s Law (which states that the number of devices on a die doubles every two years), is a reduction in device speed and performance due to device intra-level interconnection signal delays. As a result of this demand, the inclusion of low-k dielectric materials in semiconductor manufacturing processes has been instrumental in achieving these goals.Device reliability predictions, material transport properties, and failure analysis of the low-k dielectric material SiCOH using its negative magnetoresistance is presented herein. In dielectric materials, the two basic inherent conduction mechanisms are bulk-limited and electrode-limited conduction, wherein the former encompasses the electrical properties of the bulk dielectric material and the latter the physical properties of the electrode-dielectric interface. The magnitude of the magnetoresistance is related to the density of defects at the interface and within the bulk of the dielectric material. Moreover, the mean-free path (MFP) of carriers in the bulk dielectric material within the conduction band is increased in the presence of an applied external magnetic field due to the electron spin-polarization cooperative effect resulting in the suppression of the formation of singlet states and trap-mediated singlet state pair hopping due to relaxation time spin constraints supporting triplet state carrier hopping transport with a concomitant increase in current in the conduction band. Interelectrode charge carrier conduction due to defect trap states within the bulk of the material leading to dielectric breakdown is a major detractor in insulators used in industry. In this work a trap-assisted negative magnetoresistance is characterized, and a correlation is shown between the negative magnetoresistance in the amorphous dielectric material SiCOH (a-SiCOH) and failure rates in device accelerated bias-temperature stress (BTS) testing in time-dependent dielectric breakdown (TDDB) material lifetimes.

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