Tsung-Han Chiang preliminary defense

Tsung-Han will defend his dissertation! Good luck, Han!

Title:  Electrical Assessment of Dielectric Thin-Films

Abstract:  A great majority of electronic devices, from the personal computer in the late 20th century to the smart phones and tablets of the present, can attribute their success to the use of SiO2 as the gate dielectric, due to its superior insulating properties and compatibility with the Si semiconductor, in microprocessors. An understanding in the electrical properties and behavior of dielectric materials, such as SiO2, is critical for opening up new applications aside from the microprocessor industry. In this work, electrical assessment of various solution-deposited dielectric thin-films (NbPOx, LaZrO, LaAl2O3, and LiAlPO) is performed by studying the current-voltage (I-V) behavior of metal-insulator-semiconductor (MIS) devices. For high quality insulators, such as thermally-grown SiO2, a “breakover knee” can be observed in I-V behavior. Simulation of SiO2 I-V behavior reveals this “breakover knee” to be the transition point between Ohmic and Fowler-Nordhiem conduction mechanisms and is dependent on the metal-insulator barrier height (φB) and the insulator electron effective mass (m*). Additional simulation work on conduction mechanisms, including Ohmic, space-charge limited, Fowler-Nordhiem, is also performed. It is found that a high quality insulator exhibits both Ohmic and Fowler-Nordhiem, but not space-charge limited.