新型反-T狀井結構深次微米金氧半電晶體分析與模擬研究

Abstract

一種能減少寄生電容及寄生電阻並且仍能保有許多其它深次微米金氧半 場效電晶體 ( Lg=0.35, 0.25, 0.17um ) 所需的功能及製造特徵的新金 氧半電晶體結構在這裡提出.而整個模擬,包含了製程模擬程式以及元件模 擬程式的結果,用來產生元件結構以及在相同製程條件下預測傳統的以及 改良的金氧半電晶體的電特性. 由所得結果,反T狀井結構擁有許多例如 較大的飽和電流,較低的次臨界掃動,較低的最大電場強度及因衝擊游離導 致的載子最大生成率,比較寬空乏區致使寄生電容下降,以及在輕摻雜汲極 區較少的硼補償減少了寄生電阻等優點.當閘極長度縮減後,最大電場強度 的減少百分比及飽和電流的提生百分比都增加.相關的電特徵包括次臨界 及汲極導致能障降低特性,汲極特性曲線,電場強度,轉移特性(閘極電壓對 汲極電流),以及等電位曲線都被模擬出來.三級金氧半電晶體模型參數也 經配合從麥迪西程式模擬出的電壓電流曲線而萃曲出來以在傳統輕摻雜汲 極結構與改良的反T狀井結構金氧半場效電晶體中做一個完整的比較. A new MOS transistor structure which is capable of reducing the parasitic capacitance and the parasitic resistance while maintaining many other desired performance and manufacturability characteristics of deep-submicron MOSFETs (Lg=0.35,0.25,0.17um) is described.The simulations,which combines the results of the process-simulation program and the device-simulation program,are shownto generate the device structures and predict the electric characteristics ofboth the conventional and modified ITW MOSFETs under the same process condit- ion. From the results,the Inverse-T Well structure will offer many advantages suchas larger saturation current,lower subthreshold swing,the reduced magnitude ofthe maximum electric field andthe lower maximum generation rate of carriers due to impact ionization,the wider depletion region which causes the parasiticjunction capacitances to be reduced,and less boron compensation in the LDD re-gion which lowers the parasitic resistance.With the gate dimension shrinks,thereduction percentage of maximum electric field and the enhancement percentage of saturation current increase.The related electric characteristics including subthreshold and drain-induced barrier lowering ( DIBL ) characteristic,drain characteristic,electric field intensity,transferential characteristics(Vg vs.Id),and potential contours are simulated. The MOS level-3 parameters are also extracted by fitting the I-V curves obtained from simulation results of MEDICIprogram to make the complete comparision between the conventional LDD structu-es and the modified Inverse-T Well structure MOSFETs.