Single source precursor adduct

Later on, this concept was extended to precursors containing both elements of the desired material already connected by a chemical bond in a single molecule. Such precursors are mainly referred to as single source precursors. Their potential application for the deposition of thin films of the corresponding binary materials by MOCVD processes could be demonstrated. In particular Lewis acid-base adducts R3M—ER3 and four- and six-membered heterocycles [R2MER x (Fig- 1) have been in the focus of research groups both in industry and university. Consequently, the development of powerful synthetic pathways for the preparation of such precursors has been forced. 

Metal dithiophosphinates focused recent interest due to their potential use as single source precursors for low-pressure, metal-organic chemical vapor deposition (LP-MOCVD) of metal sulfides. Thus, zinc and cadmium dithiophosphinates and their phenanthroline and bipyridine adducts were characterized and used for deposition of ZnS and CdS.85,86... 

This review has described the synthesis, structure and reactivity of important classes of group 13/15 compounds such as Lewis acid base adducts and heterocycles. In addition, their potential to serve as single source precursors for the deposition of the corresponding binary materials by MOCVD process has been demonstrated. Because of the large number of compounds containing the lighter elements of group 15, N, P and As, these... 

Lewis acid-base adducts, 225-226, 229-257 as single source precursors, 299-301, 304-306... 

Abstract The review summarizes recent studies on the synthesis of M - Sb compounds and their potential application to serve as single-source precursor in MOCVD processes. General reaction pathways for the synthesis of simple Lewis acid-base adducts R3M - ER 3 and heterocycles of the type [R2MSbR 2]x (M = Al, Ga, In) are described. As-formed compounds were studied in detail in MOCVD processes using hot-wall and cold-wall reactors. Advantages as well as problems using single-source precursors are described. 

An alternative concept for the deposition of III-V material films, the so-called single-source precursor concept, was introduced by Cowley, Jones and others almost 15 years ago [10]. Typical group 13/15 single-source precursors such as Lewis acid-base adducts R3M - ER 3 or heterocycles [R2MER 2]% as shown in Scheme 1 contain the specific elements of the desired material connected by a stable chemical bond in a single molecule. 

The main advantage of as-described heterocycUc single-source precursors compared to Lewis acid-base adducts is, that these don t tend to give MSb whiskers. Unfortunately, their volatility is much lower and the MOCVD process has to be performed under high-vacuum conditions (10 -10 mbar). In addition, the precursor has to be heated up to 130 °C in order to ensure a reasonable precursor hux rate. 

Matrix isolation work and IR spectroscopy have identified the amine adducts TiF4(NH3) and TiF4(NMe3) at low temperature.29 Winter and co-workers have prepared TiCl4(NH3)2, and have used it as a single-source precursor for the deposition of TiN films.3... 

Pentahalides form essentially 1 1 adducts with sulfur, selenium, and tellurium donors, including phosphine sulfides and selenides. IR, Raman (see Raman Spectroscope, and NMR studies of the complexes formed with mixed-donor 0,S ligands showed bonding to occur via sulfur exclusively. The ionic [NbCl4()] -S2R2)][NbCle] complexes are volatile and act as a single-source precursor to mixed-Nb2 05/NbS2 films... 

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