GaN-on-SiC is preferred for RF applications because of the following characteristics.:
A. High breakdown field: GaN’s wide bandgap, allows it to achieve a high breakdown field. This means that the GaN device can operate at significantly higher voltages than many other types of semiconductor devices. However, excessively high electric fields, can cause the electrons in the device to generate high kinetic energies and result in voltage breakdown. If uncontrolled, it can cause problems for the device, not the least being degradation in performance.
B. High saturation velocity: GaN devices can run at a much higher current density. The reason is that electrons in GaN have a higher saturation velocity. GAN devices also have a higher capability for charge which leads to higher currents, a preferred characteristic in many types of RF applications since the RF power output is equal to the product of the voltage and the current. A higher voltage and current, generate higher RF power in a reasonable GAN transistor size, i.e GaN devices can be operated at higher power densities. A great feature that can be put to good use in RF power amplifiers among other applications!
C. Excellent thermal characteristics: GaN-on-SiC devices have excellent thermal properties. This is a consequence of the high thermal conductivity of SiC. As a result, GaN-on-SiC devices run cooler. A very good characteristic for any semiconductor device. A collateral result is, that the device is more reliable.
D.Piezoelectricity: GAN devices are also piezoelectric. This piezoelectricity leads to the generation of part of the charge in the device channel.
Please visit Signal Processing Group Inc., website for more on GAN as well as other topics on Analog and RF/Wireless.
Both GAN ( Gallium Nitride) and GaAs ( Gallium Arsenide) technologies and materials are important in the semiconductor industry. Specifically GAN on SiC is very important for high frequency high power circuits and Gallium Arsenide has been used in this arena for a while. In a few related posts we examine RF Integrated circuits and use of GAN technology, However, it is interesting to look at the fundamental properties of GAN and GaAs side by side. This has been done in a simple table and is available for interested readers in the Signal Processing Group Inc., website. Just click on the free articles ,,, link to access the table. In forthcoming articles and papers GAN devices, technology and applications are reviewed.
Spurious free dynamic range is a very useful parameter in receivers which allows the engineer to estimate the amount of input IP3 allowed before spurious signals start corrupting the output signal. The definitions and details of this quantity have been explored in other parts of these posts. A calculator has been developed by Signal Processing Group Inc., and is available from the free items on the SPG website for interested readers.
Image frequencies are typically generated, as a result of the heterodyning operation in a radio receiver. The result is that the receiver may malfunction. Please see previous posts on image frequency generation, image frequency rejection mixers etc, to further understand the problem. This post introduces the reader to an image frequency calculator released by Signal Processing Group Inc. to facilitate image frequency calculation given the received RF frequency and the desired IF frequency. Please access the calculator from the SPG website under the ” Free items…”link.
The superheterodyne radio receiver is one of the most popular receivers used in a broad range of radio communication systems, from broadcast to high performance two way radio,to stationary and mobile radios. An important specification of the superheterodyne radio is its image rejection. In order to understand the image rejection challenge one has to understand the basis of the image frequency. A paper released by SIgnal Processing Group Inc., and available on the SPG website is an attempt to explain this specification and its ramifications. Interested readers may access the paper under the free items link on the SPG website.