矽奈米線之幾何應力與晶體形貌效對

蕭義燁(Yi-Yeh Hsiao)

指導教授 ： 李佩雯

國立中央大學/資訊電機學院/電機工程學系/碩士(2013年)

摘要

本論文提出利用金屬矽化反應所生成的矽化鎳奈米線之幾何體積膨脹、晶體相位/形貌、電遷移以及電阻率與單晶矽奈米線的幾何尺寸大小之間具有強烈的相依性。固定鎳金屬矽化反應之溫度為500 oC的條件下，當單晶矽奈米線寬從500微縮至75 nm時，依序出現三個相位區間：分別是75-100 nm之相位為Ni31Si12、100-200 nm之相位為Ni2Si和200-500 nm之相位為Ni3Si2。此一奈米線具有多重相位的可能性之發現明顯迴異於塊材鎳金屬矽化反應生成之NiSi。此相位差異之主因應是源於高深寬比值的單晶矽奈米線提供了額外的側表面自由度，使反應形成之矽化鎳有更寬廣的自由空間以供體積膨脹，也就易於形成富含鎳相位之矽化鎳奈米線。
此外本文也研究探討將複晶矽奈米線鎳金屬矽化反應後所生成之複晶矽化鎳奈米線之電遷移與電性可靠度。發現在固定限電流的電性測試下，矽化鎳奈米線會因電遷移與局部加熱而造成奈米線的斷裂。特別是矽化鎳奈米線的電遷移會局部催化鄰近氮化矽絕緣層與矽化鎳之間的固態化學反應，造成氮化矽所釋放出之矽原子又再與矽化鎳反應之，使得燒熔斷裂之局部矽化鎳奈米線由富含鎳轉變為富含矽的矽化鎳相位。
本文所探討之幾何應力效應對於矽化鎳奈米線相位之影響以及電遷移與奈米線斷裂之分析，提供了奈米電晶體之奈米電接觸與局部電連結製作所需的材料與電性可靠度的詳細資料庫，有利於往後奈米電晶體之電極與電連結製作。

關鍵字

矽化鎳 ； 奈米線 ； 電遷移 ； 電阻率

並列摘要

We reported the experimental discoveries of geometrical volume expansion, crystallographic morphology/phase formation, electromigration and electrical resistivity of nickel silicide nanowires(NWs) strongly dependent on the geometrical size of the initially-formed single-crystalline Si (c-Si) and poly-crystalline Si (poly-Si) NWs before silicidation. There appear to have three different distinctive NWs size ranges of 200-500, 100-200 and 75-100nm-wide c-Si NWs for the generation of Ni3Si2, Ni2Si and Ni31Si12 NWs, respectively, that are generated after silicidation at of c-Si NWs 500 oC. The factor of multiple phases for NixSiy NWs formed by silicidation at 500 oC makes a distinct contrast to the single phase formation of NiSi for bulk Si silicidation at 500 oC. This reveals a c-Si NWs with a higher aspect ratio provides an additional sidewalls for accommodating the volume expansion, leading to N-rich phases instead of silicon-rich phases.
We also report the electromigration and electrical reliability of nickel polycide NWs made from fully silicidation (FUSI) of poly-crystalline Si (poly-Si) NWs. Following electrical stressing that ultimately made a nickel silicide NWs rupture due to local self-heating and electromigration of the nickel silicide NWs, a unique migration of nickel polycide NWs facilitates solid state reactions with Si3N4 layer in close proximity to them. Nickel polycide interacted with Si that is released form the dissociation of Si3N4, making the phase transformation of nickel polycide NWs from nickel-rich to silicon-rich phase near the rupture locations.
After all, we reported the geometrical strain effect on phase formation, electromigration and rupture phenomenon of nickel silicide NWs providing a detailed databases of material stability and electrical reliability for the fabrication of electrode, local metal nanocontacts and connections for Si nanoelectronic devices.

並列關鍵字

Nickel Silicide ； Nanowire ； Electromigration ； Resistivity

參考文獻

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