Atomically confined insertion for 2D strain and polarization engineered GaN electronics.

Gallium nitride semiconductors are essential for advanced electronics, but realizing their potential requires robust normally-off devices. The P-GaN gate high-electron-mobility transistor is the dominant architecture, yet its threshold voltage is restricted to less than 2 volts by the low activation efficiency of magnesium acceptors. Here, we demonstrate atomically confined insertion to overcome this bottleneck. This technique creates self-terminating, two-dimensional magnesium layers within a complex heterostructure, inducing localized strain and polarity inversion. The resulting atomic-scale polarization fields increase the average effective hole concentration several-fold. When integrated into a P-GaN gate high-electron-mobility transistor, atomically confined insertion boosts the threshold voltage from 1.5 to 4.3 volts while mitigating the degradation in transconductance and output current typical of conventional methods. Furthermore, this approach substantially suppresses the current collapse effect via an efficient vertical hole injection mechanism. This work establishes atomic-scale field engineering as a viable axis for performance control and optimization in semiconductor devices.