Wide-Bandgap Devices

Prof. Dr.-Ing. habil. Jörg Schulze

Ausbeute spielt eine wichtige Rolle in der Halbleiterindustrie. In denletzten Jahren entwickelte sich auf dem Markt fürLeistungshalbleiterbauelemente ein immer stärker wachsender Anteil derHalbleitermaterialsystemen mit weiter Bandlücke, insbesondere Siliciumcarbid(SiC). Aufgrund seiner diversen Vorteile wird SiC immer wichtiger in derLeistungselektronik. In dieser, im Vergleich zur Silicium-Technologie, nochjungen Technologie, gibt es noch einige Mechanismen, die zu verringerterAusbeuten und ve…

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Prof. Dr.-Ing. habil. Jörg Schulze

This work aims to enable a high-temperature stable 4H-SiC technology to fabricate CMOS devices.

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Prof. Dr.-Ing. habil. Jörg Schulze

Abstract zu: Towards reliable high-temperature stable SiC CMOS technology - concepts, challenges and solutions

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Prof. Dr.-Ing. habil. Jörg Schulze

Im Rahmen des Forschungsprojekts soll eine halbleiterbasierte elektrische Sicherung entwickelt, hergestellt und charakterisiert werden. Hierfür wird zunächst mithilfe von analytischer und numerischer Modellierung eine (Bauelement-) Zelltopologie konzipiert, die zur monolithischen Integration des Prinzips "thyristor dual" geeignet ist. Da JFETs für die Umsetzung des "thyristor dual" von Vorteil sind, wird im Anschluss die Realisierbarkeit einer 4H-SiC JFET Technologie innerhalb der am LEB/IISB zur…

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Prof. Dr.-Ing. habil. Jörg Schulze

Penetration of silicon carbide (SiC) power devices has recently begun in a lot of advanced power electronics applications like automotive traction inverters. A trench gate MOSFET is a proven alternative power device to the conventional planar structure due to vertical channels, which allows primarily higher cell density without JFET region and the high cell integration ultimately saves chip costs. In general, a conventional manufacturing process involves the use of a lithography mask, in which the device can be patterned by defining accordingly resist structures and areas not covered by photoresist. Thus, it is crucial to achieve the high resolution and precise alignment for a mask-conforming structure that is significantly related to systemic limitations causing further high costs. Because of technical demands of mask-aligned lithography causing high costs and the given technological limitations of the lithography systems, a self-aligned manufacturing process is favorable in this case as ion implantation process for trench MOSFETs.

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Prof. Dr.-Ing. habil. Jörg Schulze

In this work, nickel-based ohmic contacts were fabricated on the C-side of n-doped 4HSiC substrates using a short-time pulse laser, electrically characterized and analytically investigated to understand the underlying formation mechanisms compared to classical RTP. To obtain conclusions about the prevailing temperatures from the laser fluence used during alloying, a thermal simulation was created in COMSOL. This makes it possible to describe the silicidation mechanisms during laser processing in a temperature-dependent and thus system-independent manner.

For the fabrication of the ohmic contacts, the focus of the work was on the use of nickel layers, since these represent the most common metallization for low-resistance contacts on n-doped 4H-SiC. In order to evaluate the influence of different laser parameters on the contact formation mechanisms and the electrical properties of ohmic contacts, several sets of samples were prepared. The variation of the laser fluence was in the focus of the work, but also investigations on different surface pre-treatments, laser pulse durations, pulse overlaps and metallization compositions were performed.

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Prof. Dr.-Ing. habil. Jörg Schulze

Abstract zu:
Novel Approach to SIC Power Device Fabrication: High-Purity Semi-insulating Substrates Doped by Energy-Filtered Ion Implantation

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Prof. Dr.-Ing. habil. Jörg Schulze

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Martin März, Prof. Dr.-Ing.

Acting Director (2018 - 2021)

Prof. Dr.-Ing. habil. Jörg Schulze

The research project is being worked on as part of a PhD project in collaboration with the Fraunhofer Institute for Integrated Systems and Device Technology (IISB).

In this project a method to characterize the adhesion strength of thin film metallization on semiconductors is developed first. Furthermore, the degradation behavior of the adhesion strength of thin film metallization is investigated and characterized for the first time.

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Prof. Dr.-Ing. habil. Jörg Schulze

Eine Verringerung der Schaltzeiten von Leistungshalbleitern isteine wesentliche Maßnahme zur Reduzierung der Schaltverluste inLeistungsmodulen in denen (U)WBG-Transistoren genutzt werden. In konventionellenModulen können jedoch parasitäre Induktivitäten durch hohe Schaltgeschwindigkeitenzu Überspannungsspitzen und „Ringing“-Effekten führen, welche Schäden andererBauelemente im Leistungsmodul zur Folge haben können. Ein dissipativer,monolithisch in Silizium integrierter, RC-Snubber (in Reihe gesch…

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