Investigation of ALD Dielectrics in Silicon Capacitors

The goal of this analysis is to scale aluminum oxide films deposited by ALD for use in transistor fabrication with silicon and silicon-germanium substrates and the two metals offer varying work functions for gate control on the transistor level. MOS capacitors were fabricated on six-inch silicon substrates consisting of aluminum-oxide (Al2O3) as the dielectric and aluminum as the gate metal. The Al2O3 was deposited using atomic layer deposition (ALD) with thicknesses of 15nm and 20nm, while the aluminum gate metal was DC sputter deposited containing thickness of approximately 1200 A° . Capacitance values were measured in order to back-calculate the relative permittivity of Al2O3. The observed experimental relative permittivity of Al2O3 of Er = 8.83±0.55 matched reported values in literature of Er = 9.0±0.1. Future works for this project include testing different gate metals and dielectric materials for capacitance-voltage response