Chapter/Index: Introduction | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Appendix
| TEM characterization revealed that the ZrO2/poly-Si gate interface degrades at high temperatures due to the formation of Zr-silicides, e.g. nodule are formed in Figure 0140a, making ZrO2 unsuitable as a SiO2 replacement. In contrast, HfZrOx dielectrics, which incorporate ZrO2 into HfO2, show improved thermal stability and a higher dielectric constant due to the presence of tetragonal ZrO2. HfZrOx’s fine-grained microstructure also reduces oxygen vacancies. However, HfO2 films tend to crystallize and grow an interfacial layer at high temperatures (Figure 0140c), which can negatively affect device performance. Further studies can be explored on the impact of gate electrodes and interfacial reactions in HfO2 gate stacks using TEM and EELS analysis.
[1] Raghaw S. Rai and Swaminathan Subramanian, Role of transmission electron microscopy in the semiconductor industry for process development and failure analysis, Progress in Crystal Growth and Characterization of Materials, 55, pp.63-97, 2009.
|
