Selective composition modification deposition utilizing ion bombardment-induced interfacial mixing during plasma-enhanced atomic layer deposition

We investigated the effects of low-energy (<15 eV) ion bombardment on the properties of Al₂O₃ plasma-enhanced atomic layer deposition (ALD) films. High-flux ion bombardment caused interfacial mixing with underlying material of Si, and AlSiO _x films were formed instead of Al₂O₃ films. The interfacially mixed AlSiO _x films were selectively formed on single-crystal and amorphous Si surfaces, whereas normal ALD Al₂O₃ films were formed on SiO₂ surfaces. The interfacially mixed AlSiO _x films possessed thin (∼0.8 nm) SiO _x interlayers and abrupt interfaces. The interfacial mixing synthesis has the potential to realize simultaneous area and topographically selective depositions in combination with selective etching.