Investigation of n‐ and p‐type doping of GaN during epitaxial growth in a mass production scale multiwafer‐rotating‐disk reactor

n‐ and p‐doped GaN thin films have been epitaxially grown on c‐sapphire substrates by metal‐organic chemical‐vapor deposition in a production scale multiwafer‐rotating‐disk reactor. The in situ doping was performed with material having a low background carrier concentration of n∼mid‐1016 cm−3. Biscyclopentadienyl magnesium (Cp2Mg) and disilane (Si2H6) were used as the precursors for the p and n dopants, Mg and Si, respectively. The effect of mole flow on material, electrical, and optical properties was studied. We observed that both n‐ and p‐type doped GaN exhibited an excellent surface morphology, even with a high mole flow of doping precursors. After the Mg‐doped GaN was annealed in a N2 ambient at ∼700 °C for 30–60 min, the highly resistive GaN was converted into p‐type GaN with a low resistance of 0.1–1.0 Ω cm. Transmission electron microscopy showed that the defect density on the annealed Mg‐doped GaN is only 4×109 cm−2 which is of the same order as undoped GaN (1.5×109 cm−2). One of the best p‐GaN s...