金氧半電晶體的邊緣直接穿透電流之隨機擾動

Abstract

元件分離的電阻值隨著統計分布切換稱為隨機擾動雜訊(RTS)，因為流經過元件的電流類似電報訊號。眾所周知, RTS 的特性在元件分析上是非常有用的:(i)它可以用來就微觀方面探索在閘極堆疊介電層中內部以及表面的陷阱;(ii)它可以當作偵測製程所造成的潛在缺陷的敏銳工具;以及(iii)它可以用來估算奈米尺寸元件的功能極限。 打開-關閉切換的行為或是兩個級別的隨機擾動雜訊都是在低電壓下 (-1.40 V < VG < -0.77 V) 量測N型通道超薄閘介電層( 1 奈米的氧化層 + 1 奈米的氮化矽 )金氧半電晶體的邊緣直接穿透電流。起因是由於製程所造成的缺陷可以說是局部的閘極堆疊變薄(或是等效於具傳導性的漏電流蘇)。在這個非固有的狀況中，電流中電子被陷阱抓住或是電子被陷阱釋放出來的理論可以適當的解釋我們所量到的數據，尤其隨機擾動雜訊振幅的大小比例高達百分之十八。電流對電壓的特性曲線很直覺的關聯著某些個缺陷點，展現和氧化層變薄的事實十分的一致。一個敏感的監督製程的角色就像是展示出缺陷發生的機率及位置所在。

The statistical switching of the electrical resistance of a device between two discrete values is termed “random telegraph signal” (RTS) because the current through such a device resembles a telegraph signal. It is well recognized that in the case of MOS devices, characterization of RTS behaviors is very useful: (i) it can explore microscopic aspects of bulk/interface traps in gate stack dielectric; (ii) it can sensitively monitor potential defects in a manufacturing process; and (iii) it can estimate performance limits in nanodevices due to noise concern. On-off switching behaviors or two-level random telegraph signals (RTS) are measured in the low voltage (-1.40 V < VG < - 0.77 V) edge direct tunneling (EDT) currents in ultrathin gate stack (10 Å oxide + 10 Å nitride) n-channel metal-oxide-semiconductor field-effect transistors. The plausible origin is the process-induced defects in terms of localized gate stack thinning (or equivalently the conductive filament). In such extrinsic case, the current trapping-detrapping theories can adequately elucidate the data, particularly the RTS magnitude as large as 18%. The current-voltage (I-V) characteristic associated with a certain defective spot is assessed straightforwardly, showing remarkable compatibility with existing oxide thinning case. The role as a sensitive process monitor is demonstrated in terms of the occurrence probability of the defects as well as their locations.