Contamination Control Study in Grown Oxide for Reliable CMOS Operations

Contamination control in the grown oxide affects the device performance and considered as the main parameter in the fabrication process. The presence of mobile ions in the oxide shifts the flat-band voltage of the device and the key parameters responsible for this behavior are the repeatability of the process parameters and overall fabrication environment. Further cleanliness of the fabrication tool, stability of process parameters and deposition conditions can also contaminate the oxide quality. In present article various parameters such as thickness, cleanliness and process environment are studied and analyzed.

Hole trapping capability of silicon carbonitride charge trap layers

We have evaluated the hole trapping capability of the silicon carbonitride (SiCN) dielectric film for application in metal-oxide-nitride-oxide-silicon (MONOS)-type non-volatile memory devices. After a great number of holes were injected to the SiCN charge trap layer of memory capacitors at high applied voltages, the flat-band voltage shift ΔV fb,h of the capacitors was saturated and the charge centroid location of holes trapped in the SiCN layer was found to reach at 1.8–2.0 nm from the blocking oxide-charge trap layer interface. Using the obtained ΔV fb,h and charge centroid values, the maximum density of holes trapped in the SiCN layer was estimated to be 1.2 × 1013 holes/cm2, which was higher than that trapped in a silicon nitride charge trap layer (=1.0 × 1013 holes/cm2). It is concluded that the high density of trapped holes caused large ΔV fb,h in the memory capacitors with the SiCN layer.