Electrical and Computer Engineering ETDs

Publication Date

7-5-1973

Abstract

An investigation was made to determine the feasibility of using ultrahigh fluences of implanted oxygen ions to create a usable oxide layer on silicon for device applications. Previous studies have indicated that SiO2 can indeed be formed in this manner, but very little work has been reported on the electrical and structural nature of the resulting oxide-silicon interface. Six implants with fluences ranging from 1.25 x 1017 to 1 x 1018 (O2)+ /cm2 were performed into p-type silicon wafers. The implanted material was then studied to determine how the variables of anneal time, temperature, and ambient gas affected the structural and electrical characteristics of each implanted wafer. In order to make these studies, the wafers were diced into several small chips so that each chip could undergo different processing conditions. Annealing has been carried out in argon, nitrogen, and oxygen ambients at temperatures from 600 to 1200° C, for times of 0 to 62 hours. This investigation included structural studies of observable surface defects which serve to illustrate the large amounts of stress induced in the implanted silicon. Measurements of the surface profile which manifest the effects of surface sputtering and lattice expansion were made. In addition, etch studies are reported in which implanted samples were etched in successive steps to determine how the structure of the implanted layer varied as a function of depth from the surface. Aluminum electrodes were evaporated onto the implanted surface and electrical measurements of current versus voltage were made to study resistivity as a function of total ion dose and annealing conditions. Measurements of capacitance versus voltage were also made in an effort to characterize the interface region and determine the suitability of the implanted layer for device fabrication.

Document Type

Thesis

Language

English

Degree Name

Electrical Engineering

Level of Degree

Masters

Department Name

Electrical and Computer Engineering

First Committee Member (Chair)

Wayne Willis Grannemann

Second Committee Member

Harold Dean Southward

Third Committee Member

Roy Arthur Colclaser

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