- 學位論文
不對稱之電場耦合效應對超薄氧化層金氧半元件之電特性影響與其相關應用
The Asymmetric Coupling Effect on the I-V Characteristic of Ultrathin-Oxide MIS Devices and Its Applications
摘要
本篇論文主要在探討不對稱之電場耦合效應對超薄氧化層之穿隧金氧半元件之電特性影響與機制。此元件為一同心圓之結構，由內部元件以及外環所組成。在本論文之第二章，為了探討在擁有雙邊緣之環形元件中內外邊緣對飽和電流之貢獻程度，我們因此設計了特殊的光罩圖案對照組。由實驗上及模擬上的結果看來，在一環形結構中，較外部的邊緣主導了大部分的飽和電流。此外，有別於先前在探討光感測器應用時多半針對外環作為控制閘而內部元件為感測器的耦合效果做討論，在本研究中我們還將內外元件交換角色去作探討，也就是以內部為控制閘而外環為感測元件的操作情況。在角色對調後，可以看到在兩種操作情形下有明顯的差別。於是，我們提出了不對稱的耦合效應去解釋上述觀察到的相異現象，即外部耦合內部時為有效耦合但內部耦合外部時為有限耦合之概念。在用SILVACO TCAD軟體做模擬時也有觀察到上述內外耦合電場強度不相等的現象，能作為近一步的佐證。隨後在本論文之第三章，我們發現利用第二章所提及的不對稱耦合效應，在內部為控制閘而外環為感測元件的操作情況下，可以在較小的偏壓下獲得較大的光對暗電流比例，因而達到更有效率地利用能源的效果。
並列摘要
In this thesis, the asymmetric coupling effect on current-voltage characteristics of a double metal-insulator-semiconductor (MIS(p)) tunnel diode (TD) in a concentric structure has been investigated. In chapter 2, we design two sets of patterns to discuss the extent that the inner and outer fringes play in a double-fringed MIS TD with a ring structure and compare to the case of a single-fringed MIS TD. From both of the experimental and simulated results, it is noted that the outer fringe of the ring-shaped MIS(p) has a larger contribution to saturated current. Apart from the conventional operation applied for the photo-sensing purpose that the inner device serves as a sensor and the outer ring plays as the control gate (ISOG), we examine it from a contrary perspective in which the inner device and outer ring exchange their roles (IGOS). By comparing the results under these two operating modes, a distinct difference can be observed and therefore we proposed the idea of asymmetric coupling effect to account for it. The different coupling extent between inner device and outer ring is further verified by the simulated results using SILVACO TCAD. In chapter 3, we further examine the photo-sensing performance under both the ISOG and IGOS operations. It is found that by utilizing the asymmetric coupling effect in the IGOS mode, a higher light-to-dark current ratio can be achieved while a smaller bias is needed and therefore be more power-efficient.