Interface preservation during Ge-rich source/drain contact formation

• Published in: 2016 27th Annual SEMI Advanced Semiconductor Manufacturing Conference (ASMC) pp. 320 - 323
• Main Authors: Niu, C., Raymond, M., Kamineni, V., Fronheiser, J., Siddiqui, S., Niimi, H., Dechene, J. M., Labonte, A., Adusumilli, P., Carr, A. V., Shearer, J., Demarest, J., Jiang, L., Li, J., Hengstebeck, R. W.
• Format: Conference Proceeding Journal Article
• Language: English
• Published: IEEE 01.05.2016
• Subjects: CMOS integrated circuits; Contact; Drains; Electric contacts; Epitaxial growth; Germanides; Germanium oxides; Interface; Plasmas; Resists; Semiconductors; SiGe; Silicon; Silicon germanides; Silicon germanium; Strips
• ISSN: 2376-6697
• DOI: 10.1109/ASMC.2016.7491158

Contact engineering of Ge-rich source/drain is of critical importance for the development of advanced nano-scale CMOS technology nodes. Germanosilicide or Germanide contacts with low Schottky barrier height are highly desirable to achieve low contact resistance for a Ge-rich source/drain. However, practical integration of Ge-rich SiGe into devices is complicated by its unique physical and chemical properties as compared to Si-rich epitaxial SiGe. We have observed significant erosion along the SiGe interface with its dielectric cap layer. The N2-H2 remote plasma resist strip process has been shown to trigger this erosion when GeO2 exists together with SiO2 at the interface. The integrity of Ge-rich SiGe contact interface can be preserved by replacing the N2-H2 remote plasma resist strip with an O2-based photoresist ash process. Cross-sectional STEM and EDX elemental analysis have confirmed Germanide and Germanosilicide formation at the Ge-rich SiGe contact interface.