Introduction

Abstract

Successful use of ALD requires chemical precursors with sufficient volatility, thermal stability, and self-limited reactivity with surfaces. Effective ALD precursors are now known for most non-radioactive elements and many of them are commercially available. This review describes their chemical types, typical properties, and reactivity. Suitable pairs of precursors can deposit some pure elements, oxides of most elements, nitrides of many elements, sulfides, selenides and tellurides of some elements, and phosphides, arsenides, carbides, and fluorides of few elements. The mechanisms of ALD reactions involve the transfer of atoms between precursor vapors and surfaces. The transferred atoms are either hydrogen, oxygen, fluorine, or chlorine.