High-k Dielectric Passivation for GaN Diode with a Field Plate Termination

• Main Authors: Michitaka Yoshino, Fumimasa Horikiri, Hiroshi Ohta, Yasuhiro Yamamoto, Tomoyoshi Mishima, Tohru Nakamura
• Format: Article
• Language: English
• Published: MDPI AG 2016-03-01
• Series: Electronics
• Subjects: GaN; high-k; diode; power semiconductor devices; Cellium oxide
• Online Access: http://www.mdpi.com/2079-9292/5/2/15

Vertical structured Gallium nitride (GaN) p-n junction diodes with improved breakdown properties have been demonstrated using high-k dielectric passivation underneath the field plate. Simulation results at a reverse voltage of 1 kV showed that the maximum electric field near the mesa-etched p-n junction edges covered with film of dielectric constant k = 10 was reduced to 2.0 MV/cm from 3.0 MV/cm (SiO2 (k = 3.9)). The diodes were fabricated using the high-k mixed oxide of SiO2 and CeO2 with k = 12.3. I–V characteristics of the diode with a field plate showed a breakdown voltage above 2 kV with an increased avalanche resistance. This means that the electric field reduces at the periphery of the mesa-etched p-n junction and is uniformly formed across the whole p-n junction. It is clear that high-k dielectric film passivation and filed plate termination are essential techniques for GaN power devices.