Enhanced Ge n-channel gate stack performance using HfAlO high-k dielectric

Summary form only given. This work reports improved Ge n-channel gate stack performance using HfAlO high-k dielectric versus HfO₂. ALD HfAlO high-k results in improved thermal stability for a 400 °C post high-k deposition anneal of gate stacks with thick (8 nm) as well as thin (2 nm) EOT. For thick EOT stacks Al incorporation mainly benefits (10% lower) EOT and interface state density (D_it) whereas for thin EOT stacks the benefits are reduced J_g (10X) and D_it at ~matched EOT. Improvement in gate stack performance for thick EOT stacks is seen even with significantly large Al% (33%) unlike thin EOT stacks where the Al% needs to be kept low to preserve capacitance. In summary, we demonstrate a thermally stable HfAlO gate stack process with tunable Al% for improved performance vs HfO₂ over a wide EOT range.