Phosphane copper(I) complexes as CVD precursors

The synthesis of a series of phosphane copper(I) complexes of structural type [(R3P)mCuX] (R = nBu, Et, OMe; m = 2, 3; X = acetylacetonate, 4-iminopent-2-en-2-olate, picolinate, 2-(pyridin-2-yl)acetate) is presented. Possible decomposition mechanisms for these metal-organic complexes will be discussed. The use of [((MeO)3P)2Cu(acac)] (4a) and [(Et3P)3Cu(acac)] (4b) as CVD precursors in the deposition of copper onto TiN-coated oxidised silicon substrates using a low-pressure horizontal hot-wall CVD reactor at 250 °C (4a) or 350 °C (4b) deposition temperature is presented as well. Depending on the evaporation temperature and the heating rate, precursor 4a produced wire-like copper structures (particle size 650 nm, layer thickness 8.6–11.2 μm) or not completely closed layers with particle sizes of 600–1500 nm and a layer thickness of 1.1–1.4 μm. Experiments with precursor 4b resulted in the formation of non-conformal layers (crystal size 700–1100 nm, layer thickness 1.4–1.8 μm).