Epitaxy of >7 μm Thick GaN Drift Layers on 150 mm Si(111) Substrates Realizing Vertical PN Diodes with 1200 V Breakdown Voltage
S. Michler1, Y. Hamdaoui2, S. Thapa1, G. Schwalb1, S. Besendörfer3, K. Ziouche2, M. Albrecht4, F. Brunner5, F. Medjdoub2, and E. Meissner3,6
Published in:
phys. stat. sol. (a), vol. 222, no. 3, pp. 2400544 (2025).
Abstract:
Metal-organic chemical vapor deposition growth of vertical GaN PN structures on 6" Si(111) substrates enabling a 1200 V breakdown voltage is demonstrated. Thanks to an optimized buffer structure utilizing island growth in an AlN/ Al0.1Ga0.9N superlattice, the threading dislocation density is drastically reduced, and sufficient compressive stress is incorporated in active GaN layers to compensate for the thermal mismatch. Crack-free PN structures with drift layer thicknesses up to 7.4 µm are realized with a threading dislocation density of ≈5 × 108 cm-2 and an absolute wafer bow <50 µm. Quasi-vertical PN diodes reveal a linear increase in the breakdown voltage with the drift layer thickness with an average breakdown field of ≈1.6 MV cm-1. Additionally, the leakage current is shown to decrease monotonically as the drift layer thickness increases. For a 7.4 µm thick drift layer with a net ionized donor concentration of 0.9 × 1016 cm-3, a high breakdown voltage of 1200 V, a low specific on-resistance of 0.4 mΩ cm-2, and a low leakage current of 10-4 A cm-2 (at a reverse bias of 650 V) are obtained. These results demonstrate the great potential of cost-effective vertical GaN-on-Si power devices operating in the kilovolt range.
1 Siltronic AG, Einsteinstraße 172, 81677 München, Germany
2 Institute of Electronics, Microelectronics and Nanotechnology CNRS-IEMN, University of Lille, Avenue Poincaré CS60069, 59652 Villeneuve d’Ascq, France
3 Fraunhofer Institute for Integrated Systems and Device Technology IISB, Schottkystraße 10, 91058 Erlangen, Germany
4 Leibniz Institute for Crystal Growth, Max-Born-Straße 2, 12489 Berlin, Germany
5 Ferdinand-Braun-Institut (FBH), Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany
6 Chair of Electron Devices, Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstraße 6, 91058 Erlangen, Germany
Keywords:
GaN-on-Si, island growth, metal-organic chemical vapor deposition, power devices
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