Comparison of Dual-Stack Dielectric Field Plates on β-Ga₂O₃ Schottky Rectifiers

Abstract

The effects of bilayer field plates with various dielectric (SiO 2 /SiN x , Al 2 O 3 / SiN x , HfO 2 / SiN x) on Ga 2 O 3 Schottky rectifier performance were investigated. The rectifiers were fabricated on 10 μm thick, Si doped (n = 2.8 × 10 16 cm −3) β-Ga 2 O 3 epitaxial layers grown by hydride vapor phase epitaxy on Ga 2 O 3 Sn-doped substrates (n = 4.8 × 10 18 cm −3) grown by edge-defined, film-fed growth. Temperature-dependent forward current-voltage characteristics were used to extract the average Schottky barrier height of 1.14 eV ± 0.03 eV for Ni, average ideality factor of 1.02 ± 0.02, and the Richardson's constant of 48.1 A/cm 2 K 2. The reverse breakdown and leakage current were the two characteristics predominantly affected by the field plate dielectrics. The highest reverse breakdown reached was 730 V for rectifiers with Al 2 O 3 / SiN x , which was significantly higher than 562 V and 401 V for rectifiers with SiO 2 / SiN x and HfO 2 / SiN x , respectively. The on-resistance ranged from 3.8-5.0 × 10 −3-cm 2 , which was dependent on diode size, with diameters from 50 to 200 μm. This led to a power figure-of-merit (V B 2 /R ON) of 140 MW-cm 2. Design of the field plate is crucial in determining where reverse breakdown occurs.

Demonstration of Large-Size Vertical Ga2O3 Schottky Barrier Diodes

“…We believe that the vertical Ga2O3 SBDs with large device areas, which exhibit relatively high breakdown voltage, low turn-on voltage, low specific onstate resistance, and high forward current, are promising candidates for high power electronic applications. To further improve the metal/semiconductor interface, breakdown voltage, and forward current characteristics of vertical Ga2O3 Schottky barrier diodes, the future investigation will focus on optimum edge termination, low background doping level and low defect density in the Ga2O3 epitaxial layer, and surface treatment of Ga2O3 prior to metallization [30].…”

Ga2O3 and Related Ultra-Wide Bandgap Power Semiconductor Oxides: New Energy Electronics Solutions for CO2 Emission Mitigation

“…In the counter-electrode, highly doped regions beneath the metallization are deployed to assist ohmicity of the contacts [ 139 ]. The dopants for this have previously been discussed.…”

MOCVD Growth of Thick β-(Al)GaO Films with Fast Growth Rates

“…β-Ga 2 O 3 , an emerging semiconductor material, exhibits immense potential for high-power electronics attributed to its remarkable fundamental material properties, including an ultra-wide bandgap of 4.8 eV , and a high critical field strength of 8 MV/cm . The advancement of β-Ga 2 O 3 -based Schottky diodes and transistors has greatly expanded its promises for power device applications. − Moreover, the ability to control n-type doping within the range of 10 16 to 10 20 cm –3 , − the successful epitaxial growth of semi-insulating layers, , and the availability of high-quality native substrates commercially confer significant advantages to β-Ga 2 O 3 for high-power device applications. Various methods have been employed to grow Ga 2 O 3 on different oriented β-Ga 2 O 3 substrates, such as molecular beam epitaxy (MBE), ,,− pulsed laser deposition (PLD), − halide vapor phase epitaxy (HVPE), ,− low-pressure chemical vapor deposition (LPCVD), − and metalorganic chemical vapor deposition (MOCVD). ,− ,− In order to facilitate the application of high-performance power electronics with substantial breakdown capabilities, the incorporation of a thick drift layer becomes necessary.…”