Rare earth oxide for nanoelectronics
Lim, Iris Li Hwang.
Date of Issue2010
School of Materials Science and Engineering
This project primarily focus is on investigating whether the introduction of a passivation layer would allow for the formation of a more uniform coating on the Si substrate surface. The thin films are used in various devices such as metal-oxide-semiconductor (CMOS) transistors. The scaling down of modern nanoelectronic devices based on a complementary metal-oxide-semiconductor (CMOS) is done so as to increase device performance and reduce production costs. However, when the gate dielectric thickness is reduced to a few mono-layers, further thinning no longer improves the performance. This is largely due to the increasingly high gate leakage current density. The use of materials with higher dielectric constant(k) than SiO2 (k = 3.9) would allow an equivalent capacitance density to be achieved in a physically thicker insulating layer. Recently, many major research are spent on replacing the existing SiO2 gate dielectric with alternative high-k dielectric oxides such as Al2O3, ZrO2, HfO2, Zr and Hf silicates. Initially, a rare earth oxide layer (CeO2) is directly deposited on the Si substrate. However, physical characterization - AFM have shown that the required surface was not obtained. A passivation layer of either Al2O3 and TiO2 was introduced to the Si substrate. They were deposited using the Atomic Layer Deposition (ALD) process. After the successful deposition of the passivation layer, the rare earth oxide layer would then be deposited on the surface through the use of the Pulsed Laser Deposition (PLD) process. Characterization was done to determine the capacitance, dielectric value of the films and the current leakage value.
Final Year Project (FYP)
Nanyang Technological University