Recently, Three-dimensional structures such as finFETs transistors or dynamic random access memory(DRAM) require with the processing of silicon nitride(SiNx) films used for a variety of applications. Many of these same techniques can control the film thickness precisely at the atomic-scale due to the gas-phase CVD reaction mechanism. Deposited of high quality conformal SiNx thin films with a low thermal budget, atomic layer deposition(ALD) is considered a suitable technique^[1]. Especially, Plasma enhanced ALD takes advantage of the additional energy supplied from plasma to enhance the low-temperature reactivity^{[2, 3]}.

In this work, we prepared PEALD silicon nitride thin film at a wide temperature range of 250°C to 500°C using a direct N₂ plasma. The deposited silicon nitride film using CSN-2 showed a excellent step coverage and wide ALD Window. The Chemical chlorine-free precursors such as CSN-2 are considered good candidates for low-temperature PEALD SiNx Films.

References

1. George, S.M. , Chem. Rev., 110, 111–131(2010)
2. Profijt, H.B., J. Vacuum Sci. Technol. A., 29, 050801(2011)
3. Hyungjun, K.; II-Kwon, O., Jpn. J. Appl. Phys., 53, 03DA01(2014)

Fig.1. The PEALD silicon nitride film was deposited at 250°C ~ 500°C using CSN-2. (a) TEM cross-sectional images of the silicon nitride thin films prepared on a patterned wafer by PEALD. ¹Wet etch rate was evaluated using 300:1 BOE solution for 2min. At this condition, wet etch rate of thermal oxide film deposited at 770°C was a 0.28Å/sec. (b) Growth rate and refractive index as a function of deposition temperature.