Optimization of submicron Ni/Au/Ge contacts to an AlGaAs/GaAs two-dimensional electron gas

2024/08/01 by Matthew Mann, Mann, Matthew, James I. Nakamura +9
Physics and Astronomy · Engineering · #Semiconductor Quantum Structures and Devices #Semiconductor materials and devices #Nanowire Synthesis and Applications

paper · pdf · doi:10.48550/arxiv.2408.00890

Abstract

We report on fabrication and performance of submicron Ni/Au/Ge contacts to a two-dimensional electron gas in an AlGaAs/GaAs heterostructure. Utilizing scanning transmission electron microscopy, energy dispersive x-ray spectroscopy, and low temperature electrical measurements we investigate the relationship between contact performance and the mechanical and chemical properties of the annealed metal stack. Contact geometry and crystallographic orientation significantly impact performance. Our results indicate that the spatial distribution of germanium in the annealed contact plays a central role in the creation of high transmission contacts. We characterize the transmission of our contacts at high magnetic fields in the quantum Hall regime. Our work establishes that contacts with area 0.5 square microns and resistance less than 400 Ohms can be fabricated with high yield.

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