Determination of Work Functions in the Ta1−xAlxNy/HfO2 Advanced Gate Stack Using Combinatorial Methodology

Combinatorial methodology enables the generation of comprehensive and consistent data sets, compared with the “one-composition-at-a-time” approach. We demonstrate, for the first time, the combinatorial methodology applied to the work function (Φm) extraction for Ta1−xAlxNy alloys as metal gates on HfO2, for complementary metal–oxide–semiconductor applications, by automated measurement of over 2000 capacitor devices. Scanning X-ray microdiffraction indicates that a solid solution exists for the Ta1−xAlxNy libraries for 0.05 ≤ x ≤ 0.50. The equivalent oxide thickness maps offer a snapshot of gate stack thermal stability, which show that Ta1−xAlxNy alloys are stable up to 950 ◦C. The Φm of the Ta1−xAlxNy libraries can be tuned as a function of gate metal composition over a wide (0.05 ≤ x ≤ 0.50) composition range, as well as by annealing. We suggest that Ta0.9Al0.1N1.24 gate metal electrodes may be useful for p-channel metal–oxide–semiconductor applications.