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 (Phi(m)) 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 degrees C. The Phi(m) 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.