Document Type


Date of Award

Spring 5-31-1986

Degree Name

Master of Science in Electrical Engineering - (M.S.)


Electrical Engineering

First Advisor

Roy H. Cornely


Mobility, resistivity, and total impurity concentration of several purchased p-type silicon samples with known resistivities were measured by Hall effect, experiments utilizing the Van Der Pauw method. The silicon samples will serve as Hall effect standards for future measurements on other semiconductor materials, particularly gallium nitride ion cluster beam (ICB) deposited thin films. The samples which were Freshly etched with hydrofluoric acid had measurement values of 455 cm ² / V.sec, 45.9 Ω cm, and 2.6 X 1014 cm³ for mobility, resistivity, and total impurity concentration, respectively. The mobility values were within 9.9 per cent, of the published values and the accuracy of the measurement was improved by modifying the current measurement device. Exposure time of more than 30 seconds between etching and aluminum contact, deposition was found to cause errors of up to one order of magnitude in the mobility and carrier concentration measurements. X-ray diffraction using the General Electric SPG 2Spetrogoniometer and G.E. 700 measurements Detector and chart recorder] with Copper Ka radiation, had an excellent degree of accuracy and precision and showed nearly identical intensity peak locations (within 99.94%) compared with the published data for {111} and {100} silicon and the gallium samples supplied by the ICB laboratory. A gallium thin film sample proved to be polycrystalline, composed of differently oriented tiny crystallites as observed by the numerous intensity peaks at various Bragg angles. This was accounted for by discovering that, the gallium sample was evaporated onto the glass substrate rather than being deposited in the form of ion beam clusters as first, expected.



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