Selective area atomic layer deposition of rhodium and effective work function characterization in capacitor structures

Atomic layer deposition (ALD) of rhodium was investigated using rhodium(III) acetylacetonate and oxygen, and capacitance versus voltage is used to extract the effective work function in metal/insulator/semiconductor structures. Self-limiting growth was observed, and the resistivity of Rh deposited at 300°C is ∼10μΩcm, approximately a factor of 2 larger than the Rh bulk resistivity (4.3μΩcm). Selective area deposition is achieved using patterned resist layers, enabling capacitor fabrication without Rh etching. In the as-deposited state, the effective work function was measured to be 5.43 and 5.25eV on SiO2 and HfO2 dielectrics, respectively. The ALD Rh films formed under conditions used likely contain residual oxygen which can affect oxygen vacancy creation and the effective work function at the metal/dielectric interface.