2.5 kV/1.95 GW/cm² AlGaN/GaN-Based Lateral Schottky Barrier Diodes With a High-k Field Plate to Reduce Reverse Current

In this article, we present AlGaN/GaN-based lateral Schottky barrier diodes (SBDs) on sapphire substrate with fully recessed anodes and
$\text{a}\vphantom {_{\int }}$
high-permittivity field plate (FP). A specific ON-resistance of 3.2
$\text{m}\Omega \cdot $
cm2, an on/off current ratio of
$10^{{10}}$
, and a reverse breakdown voltage (BV) of 2.5 kV are simultaneously achieved for the device with the anode-to-cathode space of 30
$\mu \text{m}$
. This yields a Baliga’s power figure-of-merit (BFOM) of 1.95 GW/cm2. Our fabricated device shows that the leakage current is hardly affected by the reverse bias. It is because the electric field is pushed apart from the Schottky contact region by the high-permittivity FP. This causes the absence of the defect-related carrier tunneling effect at the Schottky contact region. Meanwhile, the high-permittivity FP helps extend the depletion effect for the drift region and gives rise to the increased BV.