[10p-E101-1~11] Frontiers of Research on Ferroelectric Semiconductors

5:05 PM - 5:35 PM JST(8:05 AM - 8:35 AM UTC)

[10p-E101-9] Electronic Device Applications of Polarization Doping in Nitride Materials

〇Yoshio Honda^1,2,3, Yuto Yamada⁴, Ryo Wakizako⁴, Takeru Kumabe⁴, Atsushi Tanaka¹, Maki Kushimoto⁴, Hiroshi Amano¹ (1.IMaSS, Nagoya Univ., 2.D Center, Nagoya Univ., 3.IAR, Nagoya Univ., 4.Grad. Sch. Eng., Nagoya Univ.)

Keywords:

Nitride semiconductors,Polarization doping,AlInGaN

Many wide-bandgap semiconductors suffer from unipolar doping behavior, in which either p-type or n-type conductivity control is difficult. In ultra-wide-bandgap semiconductors, the distinction between semiconductors and insulators becomes less clear, making conductivity control itself increasingly challenging. In nitride semiconductors, p-type control remains an important issue in GaN, and becomes more difficult with increasing Al composition, while n-type control can also become problematic. In contrast, wurtzite nitride semiconductors possess strong spontaneous and piezoelectric polarization, which has already been utilized in practical AlGaN/GaN HEMTs.In this presentation, we discuss nitride heterostructure devices based on polarization engineering, focusing on distributed polarization doping (DPD) structures and AlInGaN alloy heterostructures. Undoped n- and p-type DPD layers were grown on GaN substrates by gradually changing the Al composition. SIMS, C–V, I–V, and Hall measurements were used to evaluate polarization-induced charge, carrier density, and transport properties. In undoped DPD p–n diodes, the carrier density obtained from C–V measurements agreed well with the designed polarization charge, and clear rectifying characteristics with an ideality factor of approximately 1.6 at 473 K were obtained. In addition, electron transport in p-DPD layers was found to strongly depend on growth orientation. AlInGaN alloy growth was also investigated as a route toward more flexible control of lattice constant, bandgap, and polarization charge. Smooth step-flow surfaces were achieved, indicating the potential of AlInGaN for advanced HEMT and HBT applications.