A brief review of atomic layer deposition: from fundamentals to applications

A recent review paper on Atomic Layer Deposition with open access. The review gives an overview of ALD precursors and materials and highlights the following applications: 

• ALD in microelectronics : high-k gate dielectrics
• ALD in photovoltaics: buffer layers in Cu(In,Ga)Se2 thin film solar cells
• ALD in energy storage: Pt and YSZ for solid oxide fuel cells

A brief review of atomic layer deposition: from fundamentals to applications
Richard W. Johnson, Adam Hultqvist, Stacey F. Bent

Materials Today, Available online 10 May 2014

Abstract: Atomic layer deposition (ALD) is a vapor phase technique capable of producing thin films of a variety of materials. Base on sequential, self-limiting reactions, ALD offers exceptional conformality on high-aspect ratio structures, thickness control at the Angstrom level, and tunable film composition. With these advantages, ALD has emerged as a powerful tool for many industrial and research applications. In this review, we provide a brief introduction to ALD and highlight select applications, including Cu(In,Ga)Se2 solar cell devices, high-k transistors, and solid oxide fuel cells. These examples are chosen to illustrate the variety of technologies that are impacted by ALD, the range of materials that ALD can deposit – from metal oxides such as Zn1−xSnxOy, ZrO2, Y2O3, to noble metals such as Pt – and the way in which the unique features of ALD can enable new levels of performance and deeper fundamental understanding to be achieved.

 

 

Different multiple gate design structures where ALD gate oxides have been used. (a) A TEM cross-section of Intel's FinFET transistor at the 22 nm node with the gate-oxide and gate wrapped around the fin. (C. Auth et al. 2012 Symposium on VLSI Technology (VLSIT) (2012), pp. 131–132) (b) Liu et al. omega gate structure wrapping around a Ge channel (B. Liu et al. IEEE Trans. Electron Dev., 60 (6) (2013), pp. 1852–1860) (c) A pi-gate surrounding a poly-Si nanowire in a thin film transistor by Chen et al. (L.-J. Chen et al. IEEE Trans. Nanotechnol., 10 (2) (2011), pp. 260–265) (d) A carbon nanotube FET with a gate all around structure by Franklin et al. (A.D. Franklin et al. Nano Lett., 13 (6) (2013), pp. 2490–2495)