Atomic Layer Deposition of SiC_xN_y Using Si₂Cl₆ and CH₃NH₂ Plasma

Abstract

We developed a novel process for the atomic layer deposition (ALD) of SiC x N y films using a Si 2 Cl 6 and a CH 3 NH 2 plasma. Under self-limiting growth conditions, this ALD process led to SiC x N y films with up to 9 atomic percent carbon with a conformality >95% in 5:1 aspect ratio nanostructures. The surface reactions during ALD, and in particular the carbon incorporation mechanism, were studied using in situ attenuated total reflection Fourier transform infrared spectroscopy. Similar to the Si 2 Cl 6 and NH 3 plasmabased process, we show that on the SiC x N y growth surface, Si 2 Cl 6 reacts primarily with surface −NH 2 species that were created after the CH 3 NH 2 plasma cycle. During the subsequent CH 3 NH 2 half cycle, the surface chlorine was liberated, creating −NH x (x = 1 or 2) groups, while carbon was incorporated primarily as −NCN− species. In situ ellipsometry showed that the growth per cycle and the refractive index were ∼1 Å and ∼1.85, respectively. Elemental depth profiling with secondary ion mass spectrometry showed that, as the plasma power was increased from 50 to 100 W, the carbon atomic fraction increased from ∼4 to ∼9%. At higher plasma powers, the CH 3 NH 2 plasma half cycle was not self-limiting and led to continuous carbon nitride growth.

Progresses in Synthesis and Application of SiC Films: From CVD to ALD and from MEMS to NEMS

“…On the other hand, PEALD has been used successfully to grow SiC x O y and SiC x N y films [111][112][113][114]. Ovanesyan et al developed a novel process for the ALD of SiC x N y films using a Si 2 Cl 6 and a CH 3 NH 2 plasma.…”

“…Ovanesyan et al developed a novel process for the ALD of SiC x N y films using a Si 2 Cl 6 and a CH 3 NH 2 plasma. They reported that under self-limiting growth conditions, this ALD process led to SiC x N y films with up to nine atomic percent carbon with a conformality > 95% in 5:1 aspect ratio nanostructures [113]. In recent work, Y.-L. Hsu reported on the deposition of SiC x N y films on the aluminum (Al) substrates using PEALD method and 1,3,5-Trimethyl-1,3,5-trivinylcyclotrisilazane (C 9 H 21 N 3 Si 3 , VSZ) single-source precursor in order to construct SiC x N y -based resistive switching memory [114].…”

“…At low-temperature processes (<500 • C), PECVD-based techniques are commonly used for crystalline, nano-crystalline, and amorphous SiC film synthesis. In addition, more recently, low-temperature PEALD of SiC-based materials has demonstrated potential for growth of SiC-based materials, such as SiCO and SiCN [111][112][113][114].…”

“…Finally, from Figure 3e,f, it is possible to evidence the excellent step coverage of ALD and PEALD SiC x N y films. These techniques are very promising for the advance of future NEMS devices [111,113].…”

“…Micromachines 2020, 11, x 11 of 23 to evidence the excellent step coverage of ALD and PEALD SiCxNy films. These techniques are very promising for the advance of future NEMS devices [111,113]. Reproduced with permission from [113] published by the American Chemical Society, 2017.…”