SELECTIVE REMOVAL OF HIGH-K GATE DIELECTRICS

Abstract

Continuous downscaling of integrated circuits brought an end to the era of SiO₂. In gate dielectrics, it is being replaced by materials with high dielectric constant, so-called high-k dielectrics. One of the challenges in the integration of the high-k material is removal of those materials selectively over the substrate. This work is one of the first attempts to review current state of the art of the high-k removal. Two main approaches are discussed: dry (plasma) removal and wet removal. First, the fundamentals and limitations of both approaches are presented, then an overview of the existing experimental data is given. It is concluded that the best results could be obtained by combining the dry and wet approaches.

Keywords:

• High-k dielectrics
• High-k etching
• Plasma etching
• Wet etching

Acknowledgments

The authors would like to thank Dries Dictus and German Aksenov for fruitful discussions.

Notes

^a Sha and Chang, 2003.

^b Gray et al., 1993.

^c Sha et al., 2003.

^d Wang et al., 2006.

^e Sha et al., 2002.

The data are taken from the CRC Handbook of Chemistry and Physics (2004–2005).

If the enthalpy for crystalline material is not known, then the enthalpy for gas (g) or liquid (l) phase is listed (CRC Handbook of Chemistry and Physics (2004–2005)).

^a Sublimation point.