NAND flash擁有高存取速度、低單位成本、低功率消耗、與高儲存密度的優點，適合使用在大量儲存裝置，而現今廣泛應用在行動電子產品當中。而在本篇研究論文中，主要的研究目的在於NAND Flash的周邊電路的相關元件的元件特性與可靠度的研究。而在本篇研究論文中，使用的是在NAND Flash的周邊電路內部的高壓元件，N型空乏式高壓金氧半場效電晶體。由於高壓元件長期在高電壓的環境下操作，崩潰電壓與熱載子影響的可靠度與生命週期為相當重要的元件參數。由於探討這種類型的元件的文獻並不多，所以我們以此作為此次研究的目標。
在本論文中，我們針對不同布局參數(L&Lgd)與特殊結構(漸變接面)的N型空乏式高壓金氧半場效電晶體的特性以及熱載子影響的可靠度進行探討並進一步了解物理機制，重要的布局參數L為閘極長度，Lgd為飄移區長度。
在基本介紹過後，接著將會介紹量測元件時的設定方法與量測結果，之後再藉由電腦輔助設計模擬來觀察元件的內部變化，並推測物理機制。我們發現增加L和增加Lgd和使用漸變接面的結構會因為電場分布的改變而改善崩潰電壓、也會降低基板電流(Isub)並降低退化而使元件壽命增加。

NAND flash memory has the advantages of high access speed, low unit cost, low power consumption, and high storage density. It is also suitable for use in a mess storage devices, and has been widely applied to 3C mobile products. In this paper, the main research purpose is to study the device characteristics and reliability related to NAND flash peripheral circuit. The research in this paper uses high-voltage device which used in the peripheral circuits of NAND Flash, N-type depletion-mode high-voltage metal-oxide-semiconductor field-effect transistors. Because high-voltage device usually operated under high-voltage, the off-state breakdown voltage and hot-carrier reliability and lifetime are very important device parameters. Because there are not many literatures investigate this type of device, so we take this as the objective of this research.
In this paper, we discuss the characteristics and hot-carrier reliability of N-type depletion-mode high-voltage metal-oxide-semiconductor field-effect transistors with different layout parameters (L&Lgd) and special structures (gradual junction) and further understand the physics mechanism inside the device. The important layout parameter L is the gate length, and Lgd is the length of drift region. After the fundamental introduction, the measurement setup and methodology when measuring the device, and then we use Technology Computer Aided Design(TCAD) to simulation the internal variation, and consider the physical mechanism. We found that increasing L and increasing Lgd and using the structure of the gradual junction can improve the breakdown voltage, decrease the substrate current (Isub) and decrease the degradation to increase the lifetime of the device.

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