Electrical and Computer Engineering ETDs

Publication Date

7-1-1968

Abstract

For the last 8 years the development of nuclear detectors have been shown to have the best potentialities over the other kind of nuclear counters. In this report we studied in general the characteristics of semiconductor nuclear counters and then we experimented with two types of semiconductor detectors, the surface barrier and the diffused junction detectors. Several materials were analyzed for the fabrication of these detectors. Silicon was finally chosen because of its advantages over other materials for fabrication of semiconductor counters, such as low cost and grade of purity. Silicon wafers, n-and p- type, were obtained from Monsanto Company. The wafers had a resistivity between 1000 and 1600 ohm-cm, a diameter of about 20 mm, a thickness of 1 mm and a minimum lifetime of 200 microseconds. Surface barrier detectors were fabricated using n-and p­type silicon. In general this type of detectors is fabricated from n- type material, but p- type silicon has some advantages over n- type. One of the purpose of this work was to study the behavior of surface barriers fabricated with p- type substrate and compare them with detectors from n- type material. Diffused junction detectors were also fabricated using both types of substrates. Usually for this type of detectors a p substrate is used. The detectors were tested under a radiation flux of α paticles from Americium 241 and Plutonium 239. The results show that the surface barrier detectors fabricated from a p-type substrate had excellent resolution in relation with the detectors from an n-type substrate. Comparing these two types of detectors with the surface barriers fabricated at ORTEC Laboratories, the results were very good. The behavior of the diffused junction detectors was very poor because of its high reverse current. This problem could be caused by contamination of the wafer's surface before the diffusion compound was placed on the wafer.

Document Type

Thesis

Language

English

Degree Name

Electrical Engineering

Level of Degree

Masters

Department Name

Electrical and Computer Engineering

First Committee Member (Chair)

Harold T. Cates

Second Committee Member

Harold Dean Southward

Third Committee Member

Ahmed Erteza

Fourth Committee Member

William Byatt

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