熱載子(hot-carrier, HC)效應一直是主要的可靠度研究課題。傳統的可靠度分析,主要是探討應力測試後,臨界電壓的偏移、汲極電流的劣化程度、利用模型預估壽命、界面能態的密度(interface states density)等等。但是都沒有以MOSFET 模型的角度,去研究應力測試後,對模型參數影響的分析。在本實驗中想去分析MOSFET經熱載子應力測試後,對PSP與BSIM4模型參數的影響。 實驗使用聯華電子公司(UMC)所提供的測試晶圓。並使用盟佳科技公司所提供的MBP (Model Builder Program) 參數萃取軟體。研究主要分為以下幾個部份,第一部份,探討65奈米製程元件,MOSFET經熱載子應力測試後,如何使用MBP軟體進行參數萃取;第二部份,分別探討MOSFET經熱載子應力測試後,對PSP與BSIM4模型參數的影響; 最後是比較兩者模型所萃取出的重要參數。 在參數萃取後,可觀察到應力測試後,MOSFET特性劣化呈現在PSP模型與BSIM4模型中,其汲極電流與遷移率參數也會改變。由參數萃取的結果可以發現,汲極電流的劣化並不會貢獻在全部的公式項目中,而是在反轉層電荷密度(qim*)、β(U0×W/L)、表面電位差(ΔΨ)的項中。經由更深入的研究,除了傳統可靠度分析之外,還可以用MOSFET模型參數的角度,探討元件劣化對模型參數的改變。此外,元件經由應力測試後,可以將劣化元件的模型卡(model card)代入HSPICE中,進行電路模擬,驗證該電路是否可以通過可靠度的測試。
Hot carrier (HC) effect is a major reliability issue and has been studying these years. In traditional reliability analysis, most of researches focus on MOSFET after stress including threshold voltage shift, Id,linear degradation, Id,saturation degradation, interface states density, and lifetime prediction, etc. But there is little research discussing about the degradation from the viewpoint of MOSFET model parameters. The objective of our research is to analyze PSP and BSIM4 model parameters for MOSFETs with and without hot-carriers stress. In this research, the wafers are supplied from United Micro-electronics Corporation (UMC) and are made use of the reliability issues. The software Model Builder Program (MBP) of parameters extraction is supplied from Grand Technology Inc. (GTI). The study would be divided into the following parts. The first one is to introduce the procedure of parameters extraction by using MBP software on 65-nm-node MOSFETs with and without hot-carriers stress. Then, compare between initial and stressed MOSFET parameters by PSP model and BSIM4 model. Finally, the major parameters are compared between PSP and BSIM4 models. We observed that the degraded drain current and mobility of MOSFET after HC stress result in degraded model parameters extracted from MBP. From the result of parameter extraction, we observed that degraded drain current was not resulted from the whole components of the equation, while it was resulted from some components of the equation related to the parameters of inversion charge density (qim*), β(U0×W/L) and surface potential difference across the channel (ΔΨ). Through our research, we provide a new method to analyze the reliability from the viewpoint of MOSFET model parameters in addition to traditional reliability analysis. Furthermore, we could load the model card extracted from the degraded MOSFETs into HSPICE to execute circuit simulations (e.g. ring oscillator). It is helpful to verify the reliability test.