具閘極邊界溝槽結構之金氧半穿隧二極體之暫態電流強化行為

Enhanced Transient Current Behavior in MIS(p) Tunnel Diode with Gate Edge Trench Structure

林建宇(Jian-Yu Lin)

指導教授 ： 胡振國

國立臺灣大學/電機資訊學院/電子工程學研究所/碩士(2021年)

https://doi.org/10.6342/NTU202101152

摘要

本論文旨在研究一種新型結構的金氧半穿隧二極體，其全名為具閘極邊界溝槽結構之金氧半穿隧二極體(以下簡稱為溝槽元件)。與傳統的平面型金氧半穿隧二極體相比(以下簡稱為平面元件)，此新型結構元件在電流–電壓、記憶體留存、記憶體耐久特性中不只展現了較低的反偏壓電流，更擁有較大的暫態電流，比如說在1000個週期的記憶體耐久量測中，溝槽結構元件的記憶體電流窗口比傳統結構元件大了25倍。從高頻率的電容–電壓量測中可以推測，溝槽元件中的少數載子數量(即電子)較平面元件少，這也被認為是造成其反偏壓電流較小的原因。此外，根據以上的推論，我們提出了一個模型來解釋為何溝槽元件的暫態電流行為比平面元件要來的更強。最後，不同等效氧化層厚度對暫態電流的影響也在本論文中被詳細探討，並且我們發現溝槽元件在很大的等效氧化層厚度範圍內，都具有比平面元件更好的記憶體電流窗口。由於較強的暫態電流特性與其所致的較佳記憶體電流窗口，具閘極邊界溝槽結構之金氧半穿隧二極體擁有作為揮發性記憶體的潛力。

關鍵字

金氧半穿隧二極體 ； 暫態電流行為 ； 溝槽結構 ； 記憶體特性

並列摘要

In this thesis, a new type of metal-insulator-semiconductor (MIS) tunnel diode (TD), trench MIS TD, was investigated. From current–voltage characteristics, memory retention, and memory endurance measurements, it is found the trench MIS TDs not only have lower reverse bias current but also show stronger transient current compared to traditional planar structure MIS TDs. For example, in the 1000 cycles memory endurance test, a 25 times larger memory current window (CW) in trench devices than the CW of planar devices was observed. The reason for the lower reverse bias current is attributed to the fewer minority carriers (electrons) in trench MIS TDs, which is supported by the high-frequency C–V measurement. As for the enhanced transient behavior of trench MIS TDs, a mechanism based on the understanding of fewer minority carriers in trench devices was proposed to explain the observation. Eventually, the effect of different equivalent oxide thicknesses (EOTs) on the CW was examined. It was found that the trench devices have better memory CW in a wide EOT range. Because of the enhanced transient behavior leading to better memory CW, trench MIS TDs have the potential to serve as volatile memory devices.

並列關鍵字

metal-insulator-semiconductor (MIS) tunnel diode (TD) ； transient current behavior ； trench structure ； memory property

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