Understanding of impact of carbon doping on background carrier conduction in GaN*

Abstract

The impact of carbon doping on the background carrier conduction in GaN has been investigated. It is found that the incorporation of carbon can effectively suppress the n-type background carrier concentration as expected. Moreover, from the fitting of the temperature-dependent carrier concentration and mobility, it is observed that high nitrogen-vacancy (V N ) dominates the background carrier at room temperature which consequently results in n-type conduction. The doping agent (carbon atom) occupies the nitrogen site of GaN and forms C N deep acceptor as revealed from photoluminescence. Besides, a relatively low hole concentration is ionized at room temperature which was insufficient for the compensation of n-type background carriers. Therefore, we concluded that this background carrier concentration can be suppressed by carbon doping, which substitutes the N site of GaN and finally decreases the V N .

Alleviation of the on-state dynamic conductance decline in a GaN high electron mobility transistor with heavy carbon doping

“…[1][2][3] However, unintentional incorporation of donor impurities and the generation of donor-type point defects during heteroepitaxy often result in GaN exhibiting an n-type behavior, causing degraded device breakdown performance. 4,5) To address this, intentional introduction of C dopants as acceptors is utilized to compensate for background donors and suppress leakage currents. Incorporating a C-doped GaN (C-GaN) layer beneath the channel layer enables HEMTs to achieve superior blocking characteristics.…”