Fast-Switching Tri-Anode Schottky Barrier Diodes for Monolithically Integrated GaN-on-Si Power Circuits

Abstract

Tri-Anode GaN Schottky Barrier Diodes (SBDs) have recently shown excellent DC performance with low turn-on voltage and large breakdown thanks to their 3D contact structure around the two-dimensional electron gas (2DEG) channel. However, the 3D nature of the Tri-Anode structure is also often believed to hinder the device switching performance. In this work, we demonstrate that, on the contrary, the Tri-Anode architecture significantly enhances the device switching performance with respect to conventional planar SBDs, as shown by a substantial decrease in the recovery charge and an improvement in frequency response. The Tri-Anode SBDs excellent static and dynamic performance is then applied to a real circuit to demonstrate a monolithically integrated high-frequency Full Bridge Rectifier. These results show the potential of Tri-Anode SBDs for high-efficiency and fast-switching power integrated circuits.

Ultra-compact, High-Frequency Power Integrated Circuits Based on GaN-on-Si Schottky Barrier Diodes

“…The Tri-Anode GaN SBD significantly outperforms the Si device in terms of reverse-recovery time (trr), current (Irr) and overall charge (Qrr), and compares well to the SiC device. Such improvement comes from the superior AlGaN/GaN material properties for power applications, such as high electron mobility and large critical electric field, combined with the excellent Tri-Anode architecture [16]. The total reverse-recovery charge for the three devices, obtained from the time-integration of Irr, is reported in Table 1, which also shows a significant improvement in the Qrr•VF figure-ofmerit for the GaN Tri-Anode devices.…”

“…The GaN Tri-Anode diodes and the monolithically integrated ICs were fabricated on a 6'' GaN-on-Si heterostructure consisting of 4.2 μm of buffer, 420 nm of unintentionally-doped GaN (u-GaN) channel, 20 nm of Al0.25Ga0.75N barrier and 2.9 nm of u-GaN cap-layer. The detailed fabrication steps are reported in [16]. Scaled-up devices were achieved by a multi-finger approach, paralleling 50 fingers for a total device width of 9.9 mm.…”

Embedded Microchannel Cooling for High Power-Density GaN-on-Si Power Integrated Circuits

“…Tri-anode SBD FWBR were fabricated on an AlGaN/GaNon-silicon wafer, according the process previously described in [22] and summarized in Fig. 3(b).…”

“…concentration of electrons (1.25•10 13 cm -2 ) with high mobility (1700 cm 2 V -1 s -1 ) at the interface between AlGaN and GaN. A nanowire structure was realized in the anode region of the SBD in order to obtain high breakdown performance and to reduce turn-on voltage, as previously demonstrated in [22], [23]. The nanowires were patterned using E-beam lithography, to reach the desired nanowire width and spacing of respectively 200 nm and 100 nm, followed by an inductively coupled plasma (ICP) etching step.…”

High-Frequency GaN-on-Si power integrated circuits based on Tri-Anode SBDs

“…Another important step toward the realization of power ICs consists in the integration of high-voltage GaN diodes, which would significantly expand the design possibilities and topologies. While typical Schottky Barrier Diodes (SBDs) are not suited for high-voltage applications due to the high leakage through the Schottky barrier, lately novel architectures such as recessed anodes [6]- [9], double field plates [10], [11] and Tri-Gate/Tri-Anode hybrid structures [12]- [15] have enabled to effectively overcome this limitation, resulting in an improvement of SBDs RON vs VBR figure-of-merit. In particular, Tri-Anode GaN SBDs, in which the diode anode region is nanostructured into fins, have demonstrated superb DC performance with large breakdown voltage (VBR) up to 2 kV and low turn-on voltage [16].…”