Atomic Layer Depositon of SnO2 Thin Films for Next-Generation DRAM Electrode Applications

초록

Tin dioxide (SnO2) is a transparent conductive oxide material that is currently being investigated for potential application in DRAM electrodes, driven by the increasing demand for semiconductor scaling. The practical limitations of increasing capacitance by continuously reducing the thickness of the dielectric film have led to a growing need for new dielectric materials. Among these materials, rutile-TiO2 (k > 100) is particularly noteworthy. However, synthesizing a high-k rutile phase requires high-temperature processes exceeding 700 ˚C, which are incompatible with the CMOS process. To overcome this challenge, the rutile structure of SnO2 can be employed as a seed layer, enabling the low-temperature synthesis of rutile TiO2 via local epitaxy. In this study, we developed a method for synthesizing low-resistivity rutile SnO2 by atomic layer deposition (ALD) without the use of ozone, which has the inherent potential to oxidize the DRAM bottom electrodes. We believe that the SnO2 seeds layer can be utilized to fabricate the next generation of dielectric films, rutile TiO2, regardless of bottom electrode type.