Roland Püsche
Research Subjects
Roland Püsche has a total of 15 co-authors. Here are the top co-authors by number of shared publications:
- Alaleh Tajalli
Department of Information Engineering, University of Padova, 35151 Padova, Italy
1 shared publication - Carlo De Santi
University of Padova
1 shared publication - Davide Benazzi
Department of Information Engineering, University of Padova, 35151 Padova, Italy
1 shared publication - Elke Meissner
Fraunhofer Institute for Integrated Systems and Device Technology IISB, Department Materials, Schottkystraße 10, 91058 Erlangen, Germany
1 shared publication - Enrico Zanoni
University of Padova
1 shared publication - Farid Medjdoub
IEMN, CNRS, Université de Lille 2 , 59650 Villeneuve d'Ascq
1 shared publication
Latest Publications
- Open Access
- 17 January 2020
- Published by MDPI AG in Micromachines
- Vol. 11 (1) , 101
Vertical Leakage in GaN-on-Si Stacks Investigated by a Buffer Decomposition Experiment
We investigated the origin of vertical leakage and breakdown in GaN-on-Si epitaxial structures. In order to understand the role of the nucleation layer, AlGaN buffer, and C-doped GaN, we designed a sequential growth experiment. Specifically, we analyzed three different structures grown on silicon substrates: AlN/Si, AlGaN/AlN/Si, C:GaN/AlGaN/AlN/Si. The results demonstrate that: (i) the AlN layer grown on silicon has a breakdown field of 3.25 MV/cm, which further decreases with temperature. This value is much lower than that of highly-crystalline AlN, and the difference can be ascribed to the high density of vertical leakage paths like V-pits or threading dislocations. (ii) the AlN/Si structures show negative charge trapping, due to the injection of electrons from silicon to deep traps in AlN. (iii) adding AlGaN on top of AlN significantly reduces the defect density, thus resulting in a more uniform sample-to-sample leakage. (iv) a substantial increase in breakdown voltage is obtained only in the C:GaN/AlGaN/AlN/Si structure, that allows it to reach VBD > 800 V. (v) remarkably, during a vertical I–V sweep, the C:GaN/AlGaN/AlN/Si stack shows evidence for positive charge trapping. Holes from C:GaN are trapped at the GaN/AlGaN interface, thus bringing a positive charge storage in the buffer. For the first time, the results summarized in this paper clarify the contribution of each buffer layer to vertical leakage and breakdown.
- 17 January 2020
- Published by MDPI AG in Micromachines
- Vol. 11 (1) , 101
Open AccessVertical Leakage in GaN-on-Si Stacks Investigated by a Buffer Decomposition Experiment
We investigated the origin of vertical leakage and breakdown in GaN-on-Si epitaxial structures. In order to understand the role of the nucleation layer, AlGaN buffer, and C-doped GaN, we designed a sequential growth experiment. Specifically, we analyzed three different structures grown on silicon substrates: AlN/Si, AlGaN/AlN/Si, C:GaN/AlGaN/AlN/Si. The results demonstrate that: (i) the AlN layer grown on silicon has a breakdown field of 3.25 MV/cm, which further decreases with temperature. This value is much lower than that of highly-crystalline AlN, and the difference can be ascribed to the high density of vertical leakage paths like V-pits or threading dislocations. (ii) the AlN/Si structures show negative charge trapping, due to the injection of electrons from silicon to deep traps in AlN. (iii) adding AlGaN on top of AlN significantly reduces the defect density, thus resulting in a more uniform sample-to-sample leakage. (iv) a substantial increase in breakdown voltage is obtained only in the C:GaN/AlGaN/AlN/Si structure, that allows it to reach VBD > 800 V. (v) remarkably, during a vertical I–V sweep, the C:GaN/AlGaN/AlN/Si stack shows evidence for positive charge trapping. Holes from C:GaN are trapped at the GaN/AlGaN interface, thus bringing a positive charge storage in the buffer. For the first time, the results summarized in this paper clarify the contribution of each buffer layer to vertical leakage and breakdown.