650-V Double-Channel Lateral Schottky Barrier Diode With Dual-Recess Gated Anode

An AlGaN/GaN double-channel Schottky barrier diode (DC-SBD) with dual-recess gated anode is demonstrated in this letter. The DC-SBD features two recess steps. The deep one cuts through two channels, and the anode metal contacts 2DEG directly from the sidewall of the recessed heterostructure. The shallow one terminates at the upper channel layer and is located adjacent to the Schottky contact. A MOS field plate is placed on the shallow recess region to pinchoff the underlying channels, so the off-state leakage current of the DC-SBD can be suppressed. Since the lower channel is separated from the etched surface, the field-effect mobility beneath this MOS structure shows a high peak value of 1707 cm
²
/(V · s). The DC-SBD with an anode-to-cathode length (L
_ac
) of 15 μm exhibits a turn-on voltage (V
_T
) of ~0.6 V (at 1 mA/mm), a leakage current of 7.8 nA/mm (at -100 V), and a breakdown voltage of 704 V (at 1 μA/mm). The double-channel design also allows both the deep and shallow recesses to be terminated at GaN layers that results in high uniformity of V
_T
.