Author :
Huang, J. ; Kirsch, P.D. ; Oh, J. ; Lee, S.-H. ; Price, J. ; Majhi, P. ; Harris, H.R. ; Gilmer, D.C. ; Kelly, D.Q. ; Sivasubramani, P. ; Bersuker, G. ; Heh, D. ; Young, C. ; Park, C.S. ; Tan, Y.N. ; Goel, AN ; Park, C. ; Hung, P.Y. ; Lysaght, P. ; Choi, K
Abstract :
For the first time, we provide mechanistic understanding of high gate leakage current on surface channel SiGe pFET with high-k/metal gate to enable sub 1 nm EOT. The primary mechanism limiting EOT scaling is Ge enhanced Si oxidation resulting in a thick (1.4 nm) SiOx interface layer. A secondary mechanism, Ge doping (ges4%) in high-k, possibly by up diffusion, also results in higher leakage. With this understanding, we optimized high-k nitridation reducing O and Ge diffusion to achieve EOT=0.91 nm directly on SiGe with leakage equivalent to bulk Si. High Ion (1.5times Si), and low subthreshold slope (73 mV/dec) are also achieved. This mechanism enables high mobility channel gate dielectric development directly on SiGe without the need for Si cap, simplifying processing and device design.
Keywords :
Ge-Si alloys; diffusion; field effect transistors; hafnium compounds; high-k dielectric thin films; leakage currents; nitridation; oxidation; semiconductor doping; semiconductor materials; silicon compounds; EOT scaling; Ge doping; HfSiON-Jk-SiGe; Si oxidation; SiOx; diffusion; gate leakage currents; high mobility channel gate dielectrics; high-k nitridation; high-k-metal gate stacks; size 1.4 nm; surface channel semiconductor pFET; thick interface layer; Degradation; Dielectric devices; Germanium silicon alloys; Hafnium; High K dielectric materials; High-K gate dielectrics; Leakage current; Oxidation; Silicon germanium; Surface cleaning;
