閘極直接穿隧及邊緣直接穿隧實驗施於有縱向及橫向應力N-型通道金氧半場效電晶體

Abstract

本文研究電子自一個閘極氧化層厚度1.1奈米之N-型通道金氧半場效電晶體，因為電路佈局而產生橫向及縱向應力之下之穿隧效應。藉由三角位能井模擬器 (TRP Simulator)，並由已刊出文獻取得重要的應力物理參數，可將實驗測得之穿隧效應電流和對應閘極電壓之間萃取出橫向及縱向應力。為了檢驗上述方法之精確度，元件的載子遷移率被同時量測，並依此萃取得到和前述方法相一致之應力。接著，本文將不同應力下之源極、汲極電阻值的變化，與擴散係數做聯結，得到單位應變之活化能。 為了再證實本文之萃取方法之可靠度，藉由些微修正三角位能井模擬器，可以模擬由閘極穿隧至源極及汲極之邊緣電流 (EDT)，並可以藉此萃取出閘極與源極或汲極間之疊合處長度，觀察到□雜載子擴散遲延的效應。最後，單位應變之活化能再次被萃取，並和先前的萃取數值吻合，再次驗證了本文方法之可靠度。一個以物理為導向之可解析模擬器也在此被提出。

This thesis investigates the conduction-band electron direct tunneling current through the 1.1 nm gate oxide of n-MOSFETs transistors that undergo transverse and longitudinal stress via a layout technique. By means of the triangular potential based quantum simulator (TRP), with known process parameters and published deformation potential constants as input, fitting of measured direct tunneling current versus gate voltage leads to the quantity of the channel stress. To examine the accuracy of the method, a link with the mobility measurement on the same device is conducted. The extracted stress is in good agreement with that of the direct tunneling, and therefore the experimental data are further utilized to extract the source/drain series resistance. Relating this external resistance to the dopant diffusivity under various stress conditions can lead to the activation energy per strain. To reconfirm the validity of the above approach, the TRP simulator is again modified to deal with the edge direct tunneling counterpart. The resulting measurement data in the accumulation region furnishes the quantified gate-to-source/drain-extension overlap length. A retarded dopant diffusion phenomenon is straightforwardly observed. The corresponding strain-induced activation energy is then determined and is shown to be in good agreement with the extracted value obtained earlier. A physically oriented analytical model is therefore reached concerning the strain altered dopant diffusion.