Electrical Properties of Aluminum Oxide and Silicon Dioxide mixed oxide films deposited using Atomic Layer Deposition

This study was undertaken to demonstrate the amount of leakage current that occurs on Atomic Layer Deposed films of Silicon Dioxide, Aluminum Oxide and to compare them to a Silicon Dioxide-Aluminum Oxide mixed film. Two types of deposition were used one where the full thickness of Silicon Dioxide was deposited followed by the full thickness of Aluminum Oxide and the other where alternating layers of SiO2 and Al2O3 were deposited until the desired thickness was reached. For decades Silicon-Dioxide has been the gate dielectric material of choice due to its electrical properties. However, advancements of submicron devices have made it necessary to scale SiO₂ to thinner dimensions. Due to Silicon Dioxide’s low dielectric constant, when thickness of films scale below 2nm leakage current due to quantum tunneling increases drastically. The goal of this study is to: 1. Develop an ALD technique at a constant temperature using ozone as an oxidizer, to deposit uniform films of aluminum oxide and silicon dioxide for a dual layer film and 2. Test and compare the electrical properties of Silicon dioxide, Aluminum Oxide and the mixed oxide films and determine the Voltage Current characteristics. Ideal film thickness for electrical analysis coincides with nano-scale smoothness of surface. To determine if the samples were ideal each was tested for consistency of film and thickness using spectroscopic Ellipsometery, and roughness of film using Atomic Force Microscopy. Upon completion of photolithography, and metal liftoff the electrical properties breakdown voltage was tested using a standard electrical probe setup.