分析淺溝槽隔離所造成機械張力對奈米部分解離絕緣體上矽金氧半之電流突增現象之影響

Abstract

這篇論文探討由於淺溝槽隔離(STI)所造成的機械張力相關四十奈米部分解離絕緣體上矽N型金氧半元件(40nm PD SOI NMOS)之電流突增（kink）現象。 由實驗量測數據及2D模擬結果可驗證得到四十奈米部分解離絕緣體上矽金氧半元件中，相較於較大射級/汲級長度（S/D length）為1.7μm 的元件，較小射級/汲級長度（S/D length）為0.17μm 的元件由於受到淺溝槽隔離(STI)所造成的較大機械張力所導致其寄生雙載子電晶體(parasitic bipolar)的基極－射極(Body-Source)有較高的能帶縮減(bandgap narrowing)效應，使得其元件操作在飽和區(Saturation rigon)時之電流突增現象(kink)，會在較高的汲極電壓發生，然而在高電場時靠近汲極的能帶縮減(bandgap narrowing)效應會幫助撞擊游離(Impact Ionization)效應而產生補償效果。

This thesis reports the STI-induced mechanical stress-related kink effect behaviour of the 40nm PD SOI NMOS device. As verified by the experimentally measured data and the 2D simulation results, the kink effect behaviour in the saturation region occurs at a higher VD for the 40nm PD device with a smaller S/D length of 0.17μm as compared to the one with the S/D length of 1.7μm due to the higher body-source bandgap narrowing effect on the parasitic bipolar device from the higher STI-induced mechanical stress, offset by the impact ionization enhanced by the bandgap narrowing in the high electric field region near the drain.