Hole trapping characteristics of silicon carbonitride (SiCN)-based charge trapping memories evaluated by the constant-current carrier injection method

The hole trapping characteristics of memory capacitors with blocking oxide-silicon carbonitride (SiCN)-tunnel oxide and blocking oxide-silicon nitride-tunnel oxide stacked films were studied using the constant-current hole injection method. We evaluated the charge centroid x¯tctl of holes trapped by empty trap centers in the SiCN and silicon nitride charge trapping films. x¯tctl of trapped holes was initially located near the middle of the SiCN and silicon nitride films, and then moved toward the blocking oxide film with increasing a number of injected holes per unit area. It was also found that x¯tctl in the SiCN film was closer to the blocking oxide film as compared to that in the silicon nitride film. The location of x¯tctl of trapped holes is explained based on the hole transport in the SiCN and silicon nitride films. In addition, the flat-band voltage shift in the SiCN capacitors almost coincided with that in the silicon nitride capacitors. This result is interpreted as results of the smaller value of x¯tctl and the lower static dielectric constant of the SiCN film than those of the silicon nitride film.