Paper SS-TuP4
MORTON S. TRAUM AWARD FINALIST: Nanoparticle Growth from Copper Metal-Organic Precursors on H-terminated Silicon Surfaces

Tuesday, November 10, 2009, 6:00 pm, Room Hall 3

Scaling down of the features needed for microelectronic industry has been redefined with the advances in atomic layer deposition (ALD) methods. At the same time, chemical vapor deposition (CVD) of copper has been used in interconnect devices in the electronics industry for several decades. For a controlled copper deposition, it is desirable to combine the clean ligand removal from the precursor molecules (such as, Cu^I (hexafluoroacetylacetonato) vinyltrimethylsilane or Cu(hfac)VTMS) with the control of the ALD process.

In this work, copper nanoparticles were grown by CVD on hydrogen-terminated silicon surfaces to minimize interfacial contamination and effectively remove the hfac and VTMS ligands for clean Cu deposition. During the deposition process, the amount of copper deposited at room temperature is limited by the amount of hydrogen available for ligand removal. Both H-terminated Si(111) and Si(100) surfaces exhibit the growth of nanoparticles, as observed by AFM, and the amount of copper deposited depends on the amount of surface hydrogen present, showing similarity to ALD growth mechanism. Both AFM and SEM confirm copper nucleation. In addition, the growth kinetics of Cu(hfac)VTMS is compared for monohydrogen-terminated Si(100) and hydrogen-terminated Si(100)-3x1 using in situ MIR-FTIR. The growth on OH- and NH- terminated surfaces will be compared to that on H-terminated surfaces. In situ FTIR spectroscopic studies indicate surface reaction by analysis of the Si-H region and are compared to in situ and ex situ XPS studies to confirm metallic copper deposition. Silicon surfaces, Si(111) and Si(100), yield different results and indicate that copper growth starts at defect sites. These results set a foundation for growth of clean copper on reducing solid substrates.