title: Atomic Layer Deposition of Silicon Nitride from Bis(tert-butylamino)silane and N2 Plasma.
abstract: Atomic layer deposition (ALD) of silicon nitride (SiNx) is deemed essential for a variety of applications in nanoelectronics, such as gate spacer layers in transistors. In this work an ALD process using bis(tert-butylamino)silane (BTBAS) and N2 plasma was developed and studied. The process exhibited a wide temperature window starting from room temperature up to 500 °C. The material properties and wet-etch rates were investigated as a function of plasma exposure time, plasma pressure, and substrate table temperature. Table temperatures of 300-500 °C yielded a high material quality and a composition close to Si3N4 was obtained at 500 °C (N/Si=1.4±0.1, mass density=2.9±0.1 g/cm3, refractive index=1.96±0.03). Low wet-etch rates of ∼1 nm/min were obtained for films deposited at table temperatures of 400 °C and higher, similar to that achieved in the literature using low-pressure chemical vapor deposition of SiNx at >700 °C. For novel applications requiring significantly lower temperatures, the temperature window from room temperature to 200 °C can be a solution, where relatively high material quality was obtained when operating at low plasma pressures or long plasma exposure times.
authors: Eindhoven University of Technology , P.O. Box 513, 5600 MB Eindhoven, Netherlands.|Oxford Instruments Plasma Technology, North End, Bristol BS49 4AP, U.K.
authors: Harm C M
authors: HC
authors: Knoops
authors: Eindhoven University of Technology , P.O. Box 513, 5600 MB Eindhoven, Netherlands.
authors: Eline M J
authors: EM
authors: Braeken
authors: Eindhoven University of Technology , P.O. Box 513, 5600 MB Eindhoven, Netherlands.
authors: Koen
authors: K
authors: de Peuter
authors: Queen Mary University of London , Mile End Road, London E1 4NS, U.K.
authors: Stephen E
authors: SE
authors: Potts
authors: ASM, Pietari Kalmin katu 1 F 2, 00560 Helsinki, Finland.
authors: Suvi
authors: S
authors: Haukka
authors: ASM, Pietari Kalmin katu 1 F 2, 00560 Helsinki, Finland.
authors: Viljami
authors: V
authors: Pore
authors: Eindhoven University of Technology , P.O. Box 513, 5600 MB Eindhoven, Netherlands.
authors: Wilhelmus M M
authors: WM
authors: Kessels
keywords: ALD; Si3N4; atomic layer deposition; plasma; plasma-assisted ALD; silicon nitride; thin film; wet etch