Dynamic ON resistance study in GaN HEMT for high power switching application

Abstract

Gallium Nitride based HEMT devices are very popularly used in high power switching applications, high frequency and high voltage applications. These devices have popular applications in radar technology, military and defense-based applications, cellular and wireless communication. Their ability to maintain a high density of mobile electrons in the AlGaN/GaN interface in the form of a 2-dimensional electron gas layer makes them perfect for above mentioned applications. 2DEG electron layer paves the to a high carrier mobility. Additionally, they have several other favorable properties such as a higher bandgap, lower thermal conductivity and low critical electric field. The GaN based Power devices are showing potential to reach sales worth of US$800 million by the year 2023. Given the popularity of these devices it is of paramount interest that these devices have a reliable performance. However, these devices have several known issues. A major issue is the effect that these devices face because of the electron trapping inside the device structure. Different types of traps found in the device could lead to different means of device degradation. Trapping is when electrons in the device 2DEG channel occupy trap states in the device structure. Trapping is evident when device operates in the high voltage switching applications and as the channel loses electrons the device said to go through a current collapse. A current collapse is when the current in the device instantly drops. A device is said to have high Dynamic ON resistance when this happens. Ideal device performance takes a heavy hit as a result. Though many advancements in the field have led to a better understanding in the field of GaN power devices, there are still research gaps that need to be explored. In this project we focus on a study on the Dynamic On resistance related to these devices. We look at the causes for Dynamic on resistance and devices are tested to see the effects of Dynamic ON resistance. It is important to paint a clear picture to further understand the devices and to improve these devices for better performance