Polarization Induced High Al Composition AlGaN p–n Junction Grown on Silicon Substrates

Abstract

Wide bandgap Alx Ga1−x N (x = 0.7−1) p–n junction is realized on a silicon substrate through polarization induced doping. Polarization induced positive charge field is produced by linearly grading from AlN to Al0.7 Ga0.3 N, and negative charge field is generated by an inverted grading from Al0.7 Ga0.3 N to AlN. The polarization charge field induced hole density is on the order of 1018 cm−3 in the graded Alx Ga1−x N:Be (x = 0.7−1) p–n junction. Polarization doping provides a feasible way to mass produce III-nitride devices on silicon substrates.