Date of Award

3-4-2005

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Engineering Physics

First Advisor

Yung Kee Yeo, PhD

Abstract

Electrical activation studies of silicon implanted AlxGa1-xN grown on sapphire substrates were conducted as a function of ion dose, anneal temperature, and anneal time. Silicon ion doses of 1x1013, 5x1013, and 1x1014 cm-2 were implanted in AlxGa1-xN samples with aluminum mole fractions of 0.1 and 0.2 at an energy of 200 keV at room temperature. The samples were proximity cap annealed at temperatures from 1100 to 1350 ºC and anneal times of 20 to 40 minutes with a 500 Å thick AlN cap in a nitrogen environment. The Hall coefficient and resistivity were measured using room temperature Hall effect measurements. From this data the Hall mobility, sheet carrier concentration, and electrical activation efficiencies were calculated. Activation efficiencies of almost 100% were achieved for Al0.2Ga0.8N samples having doses of 5x1013 and 1x1014 cm-2 after annealing at 1350 and 1300 ºC, respectively, for 20 minutes. After annealing at 1250 ºC for 20 minutes, 87% efficiency was achieved for Al0.1Ga0.9N implanted with 1x1014 cm-2 silicon ions. The largest observed mobility was 89 cm2/V·s for Al0.1Ga0.9N implanted with 1x1014 cm-2 and 5x1013 cm-2 silicon ions and annealed at 1250 ºC for 20 minutes and at 1200 ºC for 40 minutes, respectively. The optimal anneal condition to maximize electrical activation efficiency and minimize nitrogen dissociation damage for Al0.1Ga0.9N was 1200 ºC anneal for 40 minutes. The mobilities, sheet carrier concentrations, and electrical activation efficiencies generally increased.

AFIT Designator

AFIT-GAP-ENP-05-08

DTIC Accession Number

ADA434437

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