- •ACKNOWLEDGMENTS
- •TABLE OF CONTENTS
- •LIST OF TABLES
- •LIST OF FIGURES
- •INTRODUCTION
- •2.1.1 Structural Properties
- •2.1.2 Physical Properties
- •2.1.3 Electrical Properties of InN
- •2.1.3.1 Background Defects
- •2.1.4 Optical Properties of InN
- •2.2.1 Thermodynamic Models in Solid Solution
- •2.2.1.1 Regular Solution Model
- •2.2.1.2 Bonding in Semiconductor Solid Solutions Model
- •2.2.1.4 Strain Energy Model
- •2.2.1.5 First-Principal Models
- •2.2.2 Thermodynamic Analysis of InN
- •2.2.3 Phase Separation in InxGa1-xN
- •2.3.1 Growth Temperature and V/III Ratio
- •2.3.2 Nitrogen Source
- •2.4 Indium Nitride (InN) Growth Techniques
- •2.4.1 Chemical Vapor Deposition (CVD)
- •2.4.1.1 Metal-Organic Vapor Phase Epitaxy (MOVPE)
- •2.4.1.2 Hydride Vapor Phase Epitaxy (HVPE)
- •2.4.1.3 Plasma Enhanced Chemical Vapor Deposition (PECVD)
- •2.4.3 Atomic Layer Deposition (ALD)
- •2.5 Substrate Materials
- •2.5.1 Sapphire Substrate (Al2O3) (0001)
- •2.5.2 Silicon (Si) Substrate
- •2.5.4 Other Substrates
- •2.5.5 Buffer Layer
- •2.6 Summary for Growth of InN on Different Substrate
- •2.6.2 Growth on Silicon (Si) Substrate
- •2.6.3 Growth on Gallium Arsenide (GaAs) Substrate
- •2.6.4 Growth on Gallium Phosphorus (GaP) Substrate
- •2.7 Overview
- •THERMODYNAMIC ANALYSIS OF InN AND InXGa1-XN MOVPE GROWTH
- •3.1 Thermodynamic Analysis of InN and InxGa1-xN
- •3.1.1 Reaction Mechanism and Kinetics of InN MOVPE
- •3.2.1 Boundary Passivation Method with Hydrogen
- •5.1. Indium Nitride (InN) Growth Optimization
- •5.1.1. Substrate Selection
- •5.1.1.1. Sapphire (c-Al2O3 (0001))
- •5.1.1.2. Gallium Nitride (GaN/c-Al2O3 (0001))
- •5.1.1.3. Silicon (Si (111))
- •5.1.2. Substrate Preparation Procedure
- •5.1.3. Metal-Organic Vapor Phase Epitaxy (MOVPE) Reactor
- •5.1.4. Growth Chemistry and Conditions for InN Growth
- •5.1.5. Indium Nitride (InN) Growth and Optimization
- •5.1.5.1. Influence of Growth Temperature
- •5.1.5.2. Influence of Substrate Nitridation
- •5.1.5.3. Influence of N/In Ratio
- •5.1.5.4. Influence of Buffer Layer and Morphological Study
- •5.1.5.5. Influence of Pressure
- •5.1.5.6. Optical and Electrical Properties
- •5.1.5.7. Summary
- •5.1.6. Indium Nitride (InN) Droplet Formation
- •5.1.7. Annealing Effect
- •5.3. Inlet Tube Modification and Growth Results
- •CONCLUSIONS
- •LIST OF REFERENCES
- •BIOGRAPHICAL SKETCH
CHAPTER 5
Indium Nitride (InN) GROWTH BY METAL-ORGANIC VAPOR PHASE EPITAXY (MOVPE)
Unlike MOVPE growth of Ga and Al nitride, it is difficult to obtain high quality InN by MOVPE because the temperature range for successful growth is very narrow (500 to 650 oC) and for alloys not well matched to that for the other III-nitrides. Part of the problem is related to the low growth temperature and the low amount of atomic nitrogen given the low decomposition efficiency of ammonia in this temperature range. Furthermore there is no obvious substrate for growth of InN.
In this chapter, results on the optimization of the growth conditions for InN are presented for several substrate and buffer layer combinations. The process variables that were manipulated are growth temperature, N/In ratio, pressure, and the buffer layer growth conditions (temperature, GaN or InN buffer layer, and nitridation). The postgrowth annealing of InN film was also studied. The reactor design was modified from a horizontal type to an extended horizontal and vertical geometry by changing the inlet tube.
5.1. Indium Nitride (InN) Growth Optimization
Optimization of MOVPE growth condition is typically accomplished by empirical studies of the key process parameters. This study concentrates on substrate selection, growth temperature, N/In ratio, buffer layer material (GaN or InN), and post-growth annealing. Several film properties are often important for a particular application (e.g., background impurity concentration, defect density, surface roughness). In general, the
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