1230 V β-Ga2O3 trench Schottky barrier diodes with an ultra-low leakage current of <1 μA/cm2

Abstract

β-Ga2O3 vertical trench Schottky barrier diodes (SBDs) are realized, demonstrating superior reverse blocking characteristics than the co-fabricated regular SBDs. Taking advantage of the reduced surface field effect offered by the trench metal-insulator-semiconductor structure, the reverse leakage current in the trench SBDs is significantly suppressed. The devices have a higher breakdown voltage of 1232 V without optimized field management techniques, while having a specific on-resistance (Ron,sp) of 15 mΩ cm2. An ultra-low leakage current density of <1 μA/cm2 is achieved before breakdown, the lowest among all reported Ga2O3 Schottky barrier diodes. Fast electron trapping and slow de-trapping near the Al2O3/Ga2O3 interface are observed by repeated C-V measurements, which show an interface state ledge and positive shifts of flat-band voltages with increasing voltage stress. By comparison between pulsed and DC measurements, the device self-heating effect and the trapping effect are uncoupled. It is found that the trapping effect at the trench sidewall affects the on-resistance of the trench SBDs, even under pulsed conditions. With reduced trapping effect and better field management technique, the trench SBDs could further harvest the promising material properties of β-Ga2O3.

Reverse Breakdown in Large Area, Field-Plated, Vertical β-Ga2O3Rectifiers

“…This also shows the relation between breakdown voltage, electric field and doping in vertical geometry rectifier consisting of a lightly doped drift region on a more heavily doped layer on a conducting substrate of these respective materials. Experimental points for Ga 2 O 3 from different groups 19,21,22,[25][26][27][28]34,35,[46][47][48]57 are also shown-these are not yet at the values achieved by the smaller bandgap SiC and GaN, where the theoretical limits are now being approached. Continued development of low defect substrates, optimized epi growth and surface treatments and improved device design and processing methods for Ga 2 O 3 are still required to push the experimental results closer to their theoretical values.…”

“…56 This data is shown in Figure 4 (bottom).The barrier height is extracted by defining the function H (J) = V -(nkT/e) In(J /A * * T 2 ) which is also equal to RAJ+n b . Using the n value determined from 102-154 MW.cm −2 , 15,16,[24][25][26][27][28][29][30] but those devices had lower total forward currents. The 760V breakdown voltage is applicable to efficient power switching in systems for photovoltaic, wind energy and motor drives.…”

Vertical β‐Ga2O3 Schottky Barrier Diodes with Enhanced Breakdown Voltage and High Switching Performance

“…In addition, for a proper ET, the epitaxial (epi) structure design is of great importance for achieving high performances in a β‐Ga 2 O 3 SBD. Unfortunately, the combination of doping concentration and thickness of the n − ‐β‐Ga 2 O 3 drift layer in this sutdy was yet to be optimized, resulting in a compromised device performance in terms of R on and V B when compared with the state‐of‐the‐art results in the literature . Futher improvement could be achieved by optimizing the parameters of the n − ‐β‐Ga 2 O 3 drift layer.…”

“…However, because of the great difficulty of doping Ga 2 O 3 into p‐type, the p–n junction‐based ET schemes that are commonly adopted in commercialized Si and SiC power devices are not applicable for Ga 2 O 3 power devices. Recently, field plate and trench metal‐oxide‐semiconductor (MOS) structures have been implemented for β‐Ga 2 O 3 ‐based SBDs to improve their voltage‐blocking capabilities by manipulating the electric field distribution at the Schottky junction edge. It was also reported that ion implantation in the device periphery to form a high‐resistivity region could be an effective ET method for improving breakdown in both GaN and SiC power diodes .…”

Understanding the Potential of 2D Ga2O3 in Flexible Optoelectronic Devices: Impact of Uniaxial Strain and Electric Field

“…Due to the wide band‐gap (4.9 eV), high break down voltage (8 MV cm −1 ), and excellent thermal stability characteristics, β‐Ga 2 O 3 has gained wide interest and has shown excellent potential applications in solar‐blind detector, transparent conductors, and gas sensors . Besides, its properties of high Baliga's figures of merit (over 3000), high breakdown field (8 MV cm −1 ), and suitability for mass production make it a promising candidate for next‐generation power devices . Until now, β‐Ga 2 O 3 has been successively applied for the power devices with superior performance, such as MESFET (Metal‐Semiconductor Field‐Effect Transistor), MOSFET (Metal Oxide Semiconductor Field‐Effect Transistor), and SBD (Schottky Barrier Diode) .…”