二氧化鋯、氧化釔4H碳化矽金氧半電容製作及分析

Abstract

本論文製作兩種金氧半電容元件，基板使用4H-SiC，氧化層使用ZrO2和Y2O3為閘極氧化層，等效於SiO2厚度為10nm，閘極使用鋁閘極，我們使用四種不同的溫度條件，基板在常溫下和基板加熱200℃及沒有退火和快速熱退火溫度500℃的組合。可以得到四種溫度環境。基板室溫加不退火；基板不加熱加退火溫度500℃；基板加熱200℃加不退火，基板加熱200℃加退火溫度500℃。 可以得到漏電流關係在Y2O3基板不加熱、不退火，電場強度為1MV/cm是10-1A/cm2，在基板加熱200℃、不退火，電場強度為1MV/cm時，漏電流為10-3A/cm2，基板不加熱、快速熱退火溫度500℃或加熱基板200℃、快速熱退火溫度500℃，電場強度為1MV/cm時，漏電流密度都是10-6A/cm2。ZrO2基板不加熱、沒有退火，電場強度為1MV/cm時，漏電流密度是10-1A/cm2，在基板加熱200℃、不退火，電場強度為1MV/cm時，漏電流密度為10-3A/cm2，基板不加熱或基板加熱200℃、快速熱退火溫度皆為500℃，電場強度為1MV/cm時，漏電流密度都是10-7A/cm2，至於C-V量測方面，在兩種薄膜的電容情況，平帶電壓有的偏移現象，可能是濺鍍造成過多的氧化層電荷在氧化層中堆積，形成偏移，但經由快速熱退火製程有達到減少氧化層電荷的作用。

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.