Interactions of moisture and organic contaminants with SiO2 and ZrO2 gate dielectric films

Susceptibility of SiO2, ZrO2, and HfO2dielectrics to moisture contamination

“…At any given temperature, the moisture adsorption capacity of ZrO 2 and HfO 2 is higher than that of SiO 2 . This trend is similar to results on moisture contamination in ppb levels (Rana et al, 2003). The moisture adsorption loading density is several times higher than the site density.…”

“…Therefore, for a given surface coverage, HfO 2 and ZrO 2 are expected to have more molecules of type 1 (those influenced by the surface). This postulate is further supported by ppb‐level moisture adsorption studies reported by Rana et al (2003). It is reported that 45–50% of the adsorbed moisture is desorbed from SiO 2 surfaces using an isothermal N 2 purge at 30°C, whereas only 20–30% is removed from ZrO 2 surfaces.…”

“…Figure 4 summarizes the effect of moisture challenge concentration on loading for SiO 2 , HfO 2 , and ZrO 2 surfaces at 24°C. The chart also includes low concentration (ppb level) data obtained in a separate study performed by Rana et al (2003). The plot indicates a type II adsorption isotherm, similar to those predicted by the Brunauer–Emmett–Teller (BET) model.…”

“…Hence, characterization of their adsorption behavior is critical. The adsorption/desorption characteristics of trace [parts‐per‐billion (ppb)] levels of moisture on SiO 2 , HfO 2 , and ZrO 2 were previously reported (Raghu et al, 2003; Rana et al, 2003). However, moisture concentrations are known to range from the high ppm to low percentage levels in a typical ambient clean room.…”

Removal of moisture contamination from porous polymeric low‐k dielectric films

“…There has been a considerable amount of research on the interactions of contaminants with high‐k dielectrics12–14; however, the mechanism of contaminant adsorption and diffusion in low‐k materials and the effect of porosity and pore structure on the mobility of contaminants have not been adequately studied and characterized. This information is critical because these materials are exposed to a wide variety of conditions during fabrication processes.…”