Search Results
High-temperature annealing of AlN films grown on 4H-SiC
2020, Brunner, F., Cancellara, L., Hagedorn, S., Albrecht, M., Weyers, M.
The effect of high-temperature annealing (HTA) at 1700 °C on AlN films grown on 4H-SiC substrates by metalorganic vapor phase epitaxy has been studied. It is shown that the structural quality of the AlN layers improves significantly after HTA similar to what has been demonstrated for AlN grown on sapphire. Dislocation densities reduce by one order of magnitude resulting in 8 × 108 cm-2 for a-type and 1 × 108 cm-2 for c-type dislocations. The high-temperature treatment removes pits from the surface by dissolving nanotubes and dislocations in the material. XRD measurements prove that the residual strain in AlN/4H-SiC is further relaxed after annealing. AlN films grown at higher temperature resulting in a lower as-grown defect density show only a marginal reduction in dislocation density after annealing. Secondary ion mass spectrometry investigation of impurity concentrations reveals an increase of Si after HTA probably due to in-diffusion from the SiC substrate. However, C concentration reduces considerably with HTA that points to an efficient carbon removal process (i.e., CO formation). © 2020 Author(s).
CrysGaN - Grundlagenentwicklung HVPE, Substrattest und -charakterisierung : Schlussbericht
2010, Richter, E., Weyers, Markus, Gründer, M., Brunner, F., Hennig, Ch., Wernicke, T, Einfeldt, S., Hartmann, M., Neumann, C.
[no abstract available]
Normally-off GaN transistors for power applications
2014, Hilt, O., Bahat-Treidel, E., Brunner, F., Knauer, A., Zhytnytska, R., Kotara, P., Wuerfl, J.
Normally-off high voltage GaN-HFETs for switching applications are presented. Normally-off operation with threshold voltages of 1 V and more and with 5 V gate swing has been obtained by using p-type GaN as gate. Different GaN-based buffer types using doping and backside potential barriers have been used to obtain blocking strengths up to 1000 V. The increase of the dynamic on-state resistance is analyzed for the different buffer types. The best trade-off between low dispersion and high blocking strength was obtained for a modified carbon-doped GaN-buffer that showed a 2.6x increase of the dynamic on-state resistance for 500 V switching as compared to switching from 20 V off-state drain bias. Device operation up to 200 °C ambient temperature without any threshold voltage shift is demonstrated.
Bereitstellung von Standards für Zusammensetzung und Dotierung von AIGaN und AIIGaN : Projekt-Abschlussbericht ; Projekt FBH 9259 ; Wachstumkern Berlin WideBaSe ; Verbundprojekt 6: Quantitative Analytik für AIInGaN-Schichtstrukturen, Teilprojekt 2: Bereitstellung von Standards für Zusammensetzung und Dotierung von AIGaN und AIInGaN ; Projektlaufzeit: 01.07.2010 bis 31.06.2013
2013, Brunner, F.
[no abstract available]
Hochbitratige Schaltungen mit InP-HBTs : Schlussbericht
2005, Heinrich, W., Brunner, F., Kurpas, P., Meliani, C., Rudolph, M., Sidorov, V., Würfl, J.
[no abstract available]
Entwicklung und Erprobung neuer Instrumente zur Bildung von Verwertungs- und Transfernetzen innerhalb der Leibniz-Gemeinschaft: Leibniz WideBaSe Research : Abschlussbericht
2009, Weyers, Markus, Brunner, F., Hübener, N., Knauer, A., Küller, V., Petzke, T., Reentilä, O., Tessaro, T., Wollweber, J., Hartmann, C., Dittmar, A., Nitschke, A., Ziem, M., Lange, P., Jendritzki, U.
[no abstract available]