Regensburg 2019 – wissenschaftliches Programm
HL 45.62: Poster
Donnerstag, 4. April 2019, 18:30–21:00, Poster E
Modifying GaAs-Heterostructures with laser-annealing — •Hans-Georg Babin, Julian Ritzmann, Marcel Schmidt, Arne Ludwig, and Andreas D. Wieck — Ruhr-Universität Bochum, D-44780 Bochum, Germany
Ex-situ modification of semiconductors is crucial for sample preparation and further experiments. For example the fabrication of ohmic contacts to the relevant structure can be decisive for the success of the conducted transport experiment.
Our goal is to use laser radiation to locally thermal anneal our samples. Due to the high power density and low spot size, it is possible to confine the thermal effects to a small area. Another benefit is the fast heating and cooling ramp when processing the sample, especially when compared to other methods like Rapid-Thermal-Annealing (RTA).
The main focus is to provide low resistance ohmic contacts to two-dimensional-electron gases (2DEG). This can be achieved by combining laser-annealing with focused-ion-beam (FIB) implantation. It is possible to produce stronger and more homogenous doping profiles compared to thermally diffused alloy contacts. Another benefit is a much lower use of thermal budget, which can be achieved by only locally heating the samples for a shorter time. This minimizes unwanted diffusion processes in the functional semiconductor structure.