Implantation and irradiation studies on mocvd grown ingan alingan and sapphire substrate

Abstract

Indium Nitride (InN), Gallium Nitride (GaN), and Aluminum Nitride (AlN) are three binary materials of III-Nitride (III-N) semiconductors and their composition tunable alloys. III-N semiconductors cover a vast wavelength ranging from infrared to ultraviolet as their band gap varies from 0.7 eV of InN to 6.2 eV of AlN, and concurrently retaining their physical and chemical properties. The advancements such as photovoltaic, blue and white Light Emitting Diodes (LEDs) based on InGaN/GaN quantum wells (QWs), and high electron mobility transistors (HEMTs) devices based on AlGaN/GaN and AlInGaN/GaN heterostructures, eventuated rapid evolution of semiconductor optoelectronic and high-frequency technology and industry. Metal Organic Chemical Vapor Deposition (MOCVD) is preferred predominantly for the mass production of GaN-based materials to meet the technological and industrial demands for various optoelectronic and high-frequency applications. MOCVD is used to grow a wide variety of III-N materials with advantages such as faster growth, few microns per hour, multi-wafer capability, higher temperature growth and quality of layers, which are difficult to grow by other epitaxial techniques. The higher concentrations of indium (In) in the InGaN layer (gt20 %) which would be effective in achieving high-efficiency solar cells has proven to be extremely challenging due to the large difference in interatomic spacing between GaN and InN. Both indium incorporation and the epilayer quality are indirectly proportional to each other with respect to growth temperature. High growth temperature (gt800 and#9702;C) results, suppression of indium incorporation due to its low decomposition temperature whereas low growth temperature dissociation of the In N bond. Thus, the indium content in the InGaN layer will be suppressed even when indium metal droplets have formed on InGaN growing surface with nitrogen vacancies (VN). Apart from indium incorporation and VN, dislocations are unavoidable one-dimensional topological defects that are found within thin films of nitride semiconductors, originating at the interface with the substrate and threading up through the active region of the device before terminating at the crystal surface. These dislocations cause a number of flaws such as degradation of the device efficiencies. It is very important for the manufacturers and designers to know the performance characteristics of GaN-based high power semiconductor switches and amplifiers for nuclear and space applications which are subjected to high levels of radiations. The irradiation studies on high power semiconductor switches and amplifiers will determine the level of radiation tolerance required by the switches and amplifiers to meet performance and reliability requirements, especially in space applications. The radiation damage is the adverse result caused by high energy radiation, which leads to extensive changes in a variety of the material properties including chemical, electric newline