查看文章

We present a quantitative model that addresses the influence of incoherent twin boundaries on the electrical properties in β-Ga 2 O 3. This model can explain the mobility collapse below a threshold electron concentration of 1× 10 18 cm− 3 as well as partly the low doping efficiency in β-Ga 2 O 3 layers grown homoepitaxially by metal-organic vapor phase epitaxy on (100) substrates of only slight off-orientation. A structural analysis by transmission electron microscopy (TEM) reveals a high density of twin lamellae in these layers. In contrast to the coherent twin boundaries parallel to the (100) plane, the lateral incoherent twin boundaries exhibit one dangling bond per unit cell that acts as an acceptor-like electron trap. Since the twin lamellae are thin, we consider the incoherent twin boundaries to be line defects with a density of 10 11–10 12 cm− 2 as determined by TEM. We estimate the influence of the incoherent …