Gallium nitride (GaN) and its alloys with aluminum or indium are in their stable form wurtzite direct band gap semiconductors which have become the most important since silicon. The excitement over III-nitrides stems from their better material and electronic properties compared to silicon and other III-V compounds, like GaAs. These properties enable the use of GaN based devices in a broad range of applications in various fields, including the automotive, military and space industries as well as in high power amplifiers for wireless base stations, and high voltage electronics for power transmission lines.
In this chapter the most used GaN based devices - light emitting diodes and high electron mobility transistors - are briefly described (see Section 1.2) together with the physical properties (see Section 1.3) that make them well suited for industrial applications. A particular class of defects, the dislocations (see Paragraph 1.4.1), greatly affects the electrical performance of GaN devices. In order to reduce their impact, it is necessary to reduce their density. The goal of this work is therefore to define some design rules for dislocation filtering in devices based on III-nitrides (see Section 1.5).