Electronic Devices

Abstract

ApplicationsThere are many potential applications of nitride-semiconductor (GaN-based FETs) electron devices because of their extremely high performance at high voltages and high frequencies [1][2][3]. This operation is possible because of the high breakdown electric field (3 × 10 6 V cm −1 , ten times larger than Si and GaAs) and electron drift velocity (2 × 10 7 cm s −1 ) at high electric fields of GaN. These properties of GaN offer major advantages in the trade-off between operating voltage and cut-off frequency that limit the operation of conventional field effect transistors. Further, the polarization effect at the AlGaN/GaN heterojunction interface results in the creation of an electron carrier density of approximately 10 13 cm −2 ; a value that is five times larger than that of AlGaAs/GaAs heterostructures. These characteristics of high frequency, high voltage and high carrier density are particularly effective in enabling the fabrication of smaller devices delivering high output power at high frequencies.A particularly important application of nitride semiconducting high frequency devices is for microwave power transmission amplifiers for third generation mobile telephone base stations [4][5][6][7]. These applications necessitate highly linear device characteristics for amplification of digitally modulated signals. Further, the use of nitride semiconductors enables high power output amplifier modules that incorporate simplified voltage-voltage converter and output matching circuits with high efficiency.There is also a growing demand for wireless technology for use in broadband internet communication such as fixed wireless access (FWA) and satellite internet access networks. These applications require high efficiency amplifiers with power ratings of ∼10 W, operating in the 22-38 GHz frequency