Regensburg 2016 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 23: Oxide Semiconductors I
HL 23.1: Vortrag
Dienstag, 8. März 2016, 09:30–09:45, H13
Method of choice for the fabrication of Schottky contacts for unipolar devices on heteroepitaxial Ga2O3 — •Daniel Splith, Stefan Müller, Florian Schmidt, Holger von Wenckstern, and Marius Grundmann — Universität Leipzig, Institut für Experimentelle Physik II, Leipzig, Germany
Ga2O3 is a promising material for a new generation of high-power devices. For the fabrication of devices like unipolar diodes or metal-semiconductor field-effect-transistors (MESFETs), the optimization of the fabrication of Schottky contacts (SCs) is crucial.
In this contribution we compare different methods for the fabrication of Pt-Schottky contacts on heteroepitaxial Ga2O3 thin films: While the rectification of SCs fabricated by standard dc-sputtering remains poor, contacts fabricated by thermal evaporation and long-throw (LT) sputtering show rectification ratios above 6 orders of magnitude and ideality factors of about 1.3 for the best contacts. Using a reactive atmosphere during the sputtering process additionally increases the barrier height from about 1 eV to values of 1.4 eV for the best contacts. Contacts comparable to those fabricated with LT sputtering can be achieved in a standard sputtering chamber by positioning the sample out of the axis of the plasma, thereby reducing the kinetic energy of the impinging particles.
We used the latter method to fabricate circular MESFETs [1] on heteroepitaxial Ga2O3 thin films. Although the channel resistances are high, on/off ratios of up to 5 orders of magnitude were achieved.
M. Higashiwaki et al., Appl. Phys. Lett. 100.1, 013504 (2012)