Modulating the Interface Chemistry and Electrical Properties of Sputtering-Driven HfYO/GaAs Gate Stacks by ALD Pulse Cycles and Thermal Treatment

Abstract

In the current work, a detailed exploration on the cleaning effect of intrinsic oxide existing at the GaAs/HfYO interface by using an atomic-layer-deposition-derived trimethylaluminum (ALD TMA) precursor as functions of TMA pulse cycles and postannealing temperature has been evaluated via X-ray photoemission spectroscopy (XPS) measurements and electrical characterization. According to XPS analyses, it can be noted that the intrinsic As oxides, Ga oxides, and As0 are effectively reduced from the HYO/GaAs gate stack after ALD TMA treatment with 20 pulse cycles. Meanwhile, optimized electrical parameters, such as the largest permittivity (k), the lowest hysteresis, and the minimum leakage density (Jg), have also been obtained for the HfYO/GaAs gate stack with 20 pulse cycles of ALD TMA. Based on the optimized pulse cycles of 20 ALD TMA, postannealing temperature-dependent interface quality and electrical performance of GaAs-based devices based on the HfYO/GaAs gate stack have also been investigated. The HfYO/GaAs/Al metal-oxide semiconductor capacitor annealed at 300 °C with optimized pulse cycles of 20 displays the greatest dielectric constant of 38, the minimum Jg of 3.28 × 10-6 A cm-2, and a small hysteresis of 0.01 V. Meanwhile, the leakage current transport mechanism at low temperature (77-327 K) has been discussed systematically.