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

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 (J _g), 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 J _g 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.