二矽化鈷和矽之電學及界面特性

Abstract

二矽化鈷是其中一個低電阻率的金屬矽化物，在半導體工業界被運用在金屬接觸。二矽化鈷有很低的電阻率，在室溫下電阻率為15 μΩ∙cm，它也是一個超導體，其臨界溫度Tc ~ 1.5 K。本論文先闡述了在矽基板上磊晶成長二矽化鈷及其晶體結構。 利用熱蒸鍍機將鈷鍍在(100)矽基板上，在熱退火的過程中，鈷會和矽反應成矽化物。利用X光繞射(XRD)和球差較正掃描穿透試電子顯微鏡(HRTEM)分析矽化物的結構。我們發現在熱退火溫度800 °C下形成的矽化物相位為二矽化鈷。在(100)矽基板上形成的二矽化鈷是多晶的結構，每個晶粒分別都是單晶並且和矽基板有磊晶的關係。 二矽化鈷和低摻雜濃度的矽接觸形成蕭基能障，和高摻雜濃度的矽接觸形成歐姆處。研究二矽化鈷和矽的界面的電學特性。

The Co disilicide(CoSi2) is one of the three silicides which has the lowest resistivity for contact and interconnect in shallow junction devices.Bulk CoSi2 was found as a superconductor with Tc ~ 1.5 K and the resistivity is about 15 μΩ-cm at 300 K; In this paper, we present the epitaxial growth of CoSi2 on Si and the crystallography of CoSi2. Cobalt was deposited on the (100) Si substrates by thermal evaporation. The region with Co was reacted with Si and transformed to silicide after annealing. The silicide was analyzed by aberration corrected high-resolution transmission electron microscope (HRTEM) and X-ray diffraction (XRD). We found that the silicide phase is CoSi2 when annealing temperature was 800 °C. The CoSi2 formed on Si (100) substrates with multiple grains as poly-crystals. Each grain of CoSi2 is single crystal with epitaxial relations with Si substrate. CoSi2 contact with low doping concentration Si to form Schottky barrier, contact with high doping concentration Si to form ohmic contact. The electrical properties of the interface of CoSi2and Si have been studied.