Modulation of NiGe/Ge Contact Resistance by S and P Co-introduction

Abstract

S and P co-introduced NiGe/Ge (SP-NiGe/Ge) diodes are investigated to reduce the contact resistance Rc of NiGe/n-Ge and to increase the Rc of NiGe/p-Ge to realize metal source/drain Ge n-channel metal–oxide–semiconductor field-effect transistors (nMOSFETs). SP-NiGe/Ge diodes show similar profiles to the mixture of S-introduced NiGe/Ge (S-NiGe/Ge) and P-introduced NiGe/Ge (P-NiGe/Ge) diodes. In SP-NiGe/Ge diodes, not P but S segregation is observed. The lowest Rn/Rp value, where Rn (Rp) is the differential resistance R of NiGe/n-Ge (NiGe/p-Ge) diode, is obtained for NiGe/Ge diodes fabricated at 350 °C. It is revealed that SP-NiGe/Ge diodes can reduce the Rn and increase the Rp more than S-NiGe/Ge and P-NiGe/Ge diodes.