Growth and characterization of Si-doped cubic GaN

We grew Si-doped cubic GaN layers having Si concentrations in the range between 5x10(18) and 1x10(20)cm(-3). The electron mobility and carrier concentration were 95 cm(2)V(-1)s(-1) and 6.7x10(19)cm(-3), respectively, when the Si concentration was 9.2x10(19)cm(-3). This mobility is almost equal to that of hexagonal GaN with high Si concentration. The sheet resistance was highly anisotropic when the Si concentration of the specimen was lower than 2x10(19)cm(-3). The number of stacking faults in the (111) plane in the [110] direction was higher than that in [1 (1) over bar0]. Since the stacking faults of (111) are hexagonal GaN phase, we think the sheet resistance anisotropy was caused by barriers between the cubic and hexagonal GaN phases.