Fabrication and analysis of 4H-SiC MOS Capacitor with High-k Gate Dielectrics:ZrO2,Y2O3
Date Issued
2012
Date
2012
Author(s)
Chung, Cheng-Yueh
Abstract
In this research, we design two kinds of MOS-Capacitors with ZrO2 and Y2O3 as the insulators. (Equivalent Oxide Thickness, EOT) EOT is 10nm.Therefore, ZrO2 and Y2O3 were deposited on substrates at different substrate temperature (room temperature and 200℃) and then (Rapid Thermal annealing, RTA) at 500℃.We can get four kinds of temperature conditions. Condition1：Tsubtrate is room temperature, and Tannealing is room temperature. Condition2：Tsubtrate is room temperature, and Tannealing is 500℃.Condition3：Tsubtrate is 200℃. and Tannealing is room temperature.Condition4：Tsubtrate is 200℃,and Tannealing is 500℃.
We report the C-V, I-V electrical measurement results of MOS capacitors using Y2O3 thin film deposited by RF sputtering. The leakage current density is about 10-3A/cm2 at 0.5MV/cm in condition 1.The leakage current density is about 10-3A/cm2 at 1MV/cm in condition 2.The leakage current density is about 10-3A/cm2 at 1.5MV/cm in condition 3.The leakage current density is about 10-3A/cm2 at 1.6MV/cm in condition 4.ZrO2 thin film deposited by RF sputtering. The leakage current density is about 10-3A/cm2 at 0.5MV/cm in condition 1. The leakage current density is about 10-3A/cm2 at 1MV/cm in condition 2. The leakage current density is about 10-3A/cm2 at 0.8MV/cm in condition 3. The leakage current density at 1MV/cm is about 10-3A/cm2 at 2.7MV/cm in condition 3, and condition 4.
According to the results, the ZrO2 thin film is better than Y2O3 for the leakage current. the C-V measurement result of MOS capacitors using Y2O3 and MOS capacitors using ZrO2，the flat band voltage is shift. The possible reason is more fixed oxide charge and mobile ion charge in oxide layer. We have reduced charge in oxide layer by RTA process.
Subjects
MOS-capacitor
SiC
RF sputter
Gate insulators
RTA
Y2O3
ZrO2
Type
thesis
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