An MOCVD Approach to High‐k Praseodymium‐Based Films

Abstract

New high-k dielectric thin films have become of increasing interest over the last few years in the search for an alternative material to SiO 2 gate insulators in MOS devices. Lanthanide oxides have been studied as potential candidates for SiO 2 replacement. In this review, a description of the different CVD approaches to fabricating praseodymium oxide and silicate films with dielectric properties is presented. In particular, thermally activated and liquid-injection metal-organic (MO) CVD as well as atomic layer deposition (ALD), developed in recent years, are discussed. Examples highlighting the importance of different praseodymium precursors on the deposited phases are given. Special emphasis is placed upon deposition parameters crucial to obtain Pr 2 O 3 films and upon interfacial characterization. In addition, dielectric properties have been correlated to structural and compositional characteristics of praseodymium-containing films.

Growth and structure of ultrathin praseodymium oxide layers on ruthenium(0001)

“…The study of thin films of praseodymia has so far been limited to films on silicon substrates grown by physical vapor deposition (PVD) or chemical vapor deposition (CVD), mostly in the context of microelectronic applications. 14,18 To the best of our knowledge, only one study exists on praseodymia films grown on a Ru(0001) metal substrate, focusing on CO and C 2 H 4 adsorption on Rh loaded films. 19 However, in that particular study the praseodymia film was not crystalline and did not exhibit a diffraction pattern, rendering an atomistic interpretation of the role of the oxide virtually impossible.…”

Lanthanide N,N-Dimethylaminodiboranates as a New Class of Highly Volatile Chemical Vapor Deposition Precursors

“…Lanthanide precursors that do have sufficient volatility for CVD and ALD applications typically employ anionic ligands that either are sterically bulky, such as silylamides, − or are multidentate (or polyhapto), such as β-diketonates, − cyclopentadienyls, − amidinates, − and guanidinates. − Neutral chelating donors (such as glymes) are often employed to fill remaining vacancies in the coordination sphere, sometimes by grafting them onto the anionic ligands. Examples of these ligand types include ether-functionalized β-ketoiminates , and alkoxides. − Several reviews of lanthanide precursors and their use in CVD and ALD have been published. ,,,,− …”

Lanthanide N,N-Dimethylaminodiboranates: Highly Volatile Precursors for the Deposition of Lanthanide-Containing Thin Films

“…The development of improved lanthanide-containing precursors suitable for chemical vapor deposition (CVD) and atomic layer deposition (ALD) is a significant technological goal. − Lanthanide materials have optical, − electrical, − and magnetic − properties that make them useful in many applications such as phosphors in LEDs and lasers and as high-κ dielectrics for microelectronic transistors. Ideal CVD and ALD precursors are highly volatile and deposit films cleanly and conformally (i.e., with uniform thickness) in trenches and vias with high aspect ratios (>5:1)…”