Knowledge

1.2Gallium Nitride(GaN)-Definition

1.2Gallium Nitride(GaN)-Definition Despite the fact that GaN has been studied far more extensively than the other group III nitrides, further investigations are still needed to approach the level of understanding of technologically important materials such as Si and GaAs. GaN growth often suffers from large background n-type carrier concentrations because of native defects and, [...]

1.2.1 Chemical Properties of GaN

1.2.1 Chemical Properties of GaN Since Johnson et al. [139] first synthesized GaN in 1932, a large body of information has repeatedly indicated that GaN is an exceedingly stable compound exhibiting significant hardness. It is this chemical stability at elevated temperatures combined with its hardness that has made GaN an attractive material for [...]

1.2.2 Mechanical Properties of GaN

1.2.2 Mechanical Properties of GaN GaNhas a molecular weight of 83.7267 g mol1 in the hexagonalwurtzite structure.The lattice constant of early samples of GaN showed a dependence on growth conditions, impurity concentration, and film stoichiometry [151]. These observations were attributed to a high concentration of interstitial and bulk extended defects. A case in point [...]

1.2.3 Thermal Properties of GaN

1.2.3Thermal Properties of GaN The lattice parameter of semiconductors depends on temperature and is quantified by thermal expansion coefficient (TEC), which is defined as Da/a or aa and Dc/c or ac, for in-plane and out-of-plane configurations, respectively. It depends on stoichiometry, extended defects, and free-carrier concentration. As in the case of the lattice parameter, [...]

1.1Crystal Structure of Nitrides

1.1Crystal Structure of Nitrides Group III nitrides can be of crystalline structures: the wurtzite (Wz), zinc blende (ZB), and rock salt. Under ambient conditions, the thermodynamically stable structure is wurtzite for bulk AlN, GaN, and InN. The zinc blende structure for GaN and InN has been stabilized by epitaxial growth of thin films [...]

General Properties of Nitrides

Introduction GaN as a representative of its binary cousins, InN and AlN, and their ternaries along with the quaternary, is considered one of the most important semiconductors after Si. It is no wonder that it finds ample applications in lighting and displays of all kinds, lasers, detectors, and high-power amplifiers. These applications stem [...]

5-1 Introduction

5-1 Introduction Silicon carbide (SiC)-based semiconductor electronic devices and circuits are presently being developed for use in high-temperature, high-power, and high-radiation conditions under which conventional semiconductors cannot adequately perform. Silicon carbide’s ability to function under such extreme conditions is expected to enable significant improvements to a far-ranging variety of applications and systems. These range [...]

5-2-1 SiC Material Properties

SILICON CARBIDE (SiC) materials are currently metamorphosing from research and development into a market driven manufacturing product. SiC substrates are currently used as the base for a large fraction of the world production of green, blue, and ultraviolet light-emitting diodes (LEDs). Emerging markets for SiC homoepitaxy include high-power switching [...]

5-2-1-1 SiC Crystallography

5-2-1-1 SiC Crystallography Silicon carbide occurs in many different crystal structures, called polytypes. Despite the fact that all SiC polytypes chemically consist of 50% carbon atoms covalently bonded with 50% silicon atoms, each SiC polytype has its own distinct set of electrical semiconductor properties. While there are over 100 known [...]

5-2-1-2 Electrical Properties

5-2-1-2 Electrical Properties Owing to the differing arrangement of Si and C atoms within the SiC crystal lattice, each SiC polytype exhibits unique fundamental electrical and optical properties. Some of the more important semiconductor electrical properties of the 3C, 4H, and 6H SiC polytypes are given in Table 5.1. Much more detailed electrical [...]