28 nm堆疊式HK/MG nMOSFETs的特性與突出效應

Characteristics and Kink Effect of 28 nm nMOSFETs with HK/MG Stacks

陳文聖(Wen-Sheng Chen)

指導教授 ： 黃恆盛

共同指導教授 ： 王木俊(Mu-Chun Wang)

國立臺北科技大學/機電學院/機電整合研究所/碩士(2014年)

摘要

目前，引用高介電係數(HK)的材料替換傳統的氮氧化矽(SiON)已成為勢在必行的做法，然而，隨著科技迅速的發展，閘極氧化層厚度仍面臨到漏電流可容忍的極 限，因此，人們勢必得發展出更新穎的技術，才能有效的克服閘極可靠度議題。
本研究採用聯華電子股份有限公司28奈米製程的晶圓做為實驗試片，利用三種不同氮化製程的晶圓做比較，閘極介電層則採用堆疊式的結構(氧化鋯鉿; HfOx/ZrOy/HfOz)，通道寬度一律採用1 μm做為實驗樣本，而通道長度分成三種尺寸做探討，分別為1 μm、0.12 μm、0.033 μm，操作溫度為: 25℃、75℃、125℃。
本論文是採用源極浮接的實驗方式進行探討，閘極由負電壓掃描到零伏特時發現，汲極電流曲線在閘極電壓為-0.62V時，有一個突出(kink)現象的產生，同樣條件下進行反向掃描，此現象卻出現在閘極電壓為-0.64V時，為確認此效應的原因，我們利用不同操作溫度進行實驗。結果顯示，此現象隨溫度的變化有一致的趨勢，皆隨著操做溫度的上升而往電晶體的反轉區(inversion region)移動。此外，我們也發現這個突出現象(kink)的產生與大量的閘極漏電流導致空乏區變化有著密切的關係，因此我們認為當VG = -0.62V時，汲極與基底的空乏區內產生類似電荷捕捉和釋放的行為，造成汲極電流瞬間有突出的現象。

關鍵字

高介電係數 ； 耦合電漿氮化 ； 突出現象 ； 氧化鋯鉿 ； 高電場效應

並列摘要

Recently, that is an imperative method to introduce high-k materials replacing the conventional oxynitride to be gate dielectrics. However, with the technique development fast, the physical gate oxide thickness still come to a critical range for the gate leakage. Therefore, people must be to create or find out the more avant-garde technology to resolve that, the gate oxide issues of reliability.
The experimental devices were fabricated from 28 nm node high performance logic technology of United Micro-electronics Corporation (UMC). The process of HfZrOx dielectric layer was deposited by atomic layer deposition (ALD) technology. The wafers were then annealed with different annealing temperatures and nitrogen concentrations after ALD. In this research, the different experimental temperatures (25℃, 75℃ and 125℃) and channel lengths (1 μm, 0.12 μm and 0.033 μm) are included in the experiment.
In this study, the gated diode metrology with source terminal floating was adopted. The experimental results indicated that the drain current had a kink effect at VG = -0.62V, when the gate voltage (VG) was swept from –Vcc to 0V. In the contrary, it happened at VG = -0.64V when VG was swept reversely. In order to make sure this phenomenon, the different operating temperatures were raised and the analytical consequence showed that, it had a consistent trend with stress temperature. Therefore, we found that the kink effect is related with greatly gate-to-bulk tunneling leakage inducing the variation of junction width in the drain terminal. So, we observe that a similar “trapping and de-trapping” phenomenon was happened at this gate voltage point, inducing this kink effect of the drain current.

並列關鍵字

High-k ； DPN ； Kink effect ； HfZrOx ； High field effect

參考文獻

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