Investigation of poly-Si 1-x Ge x for dual-gate CMOS technology

Wen Chin Lee*, Ya Chin King, Tsu Jae King, Chen-Ming Hu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


Poly-Si 1-x Ge x -gated MOS capacitors were fabricated with x varying from 0 to 0.5. NMOS and PMOS C-V characteristics were measured. Reduced poly-gate depletion effect (PDE) was observed in PMOS devices with increasing Ge mole fraction; while for NMOS, devices with a Ge content ∼20% exhibit the least PDE. Higher active dopant concentration and reduced gate-depletion width for devices featuring less PDE were confirmed. Work function difference (ΦMS) was found to decrease slightly in N + films and significantly in P + films as Ge content increases. The shift in ΦMS for N + poly-Si 1_x Gex is negligible while it is -0.13 V for P + Si 0.8 Ge 0.2 and -0.32 V for P + Si 0.5 Ge 0.5 . The reduction in energy bandgap (ΔE g ) was also determined to increase from 0 to 0.26 eV as Ge content increases from 0 to 50%. For deep submicron dual-gate CMOS application, the shift in ΦMS should be minimized for low and symmetrical V th as well as improved short-channel effect (SCE). A Ge content of ∼20% therefore seems to offer the best tradeoff between SCE and PDE.

Original languageEnglish
Pages (from-to)247-249
Number of pages3
JournalIEEE Electron Device Letters
Issue number7
StatePublished - 1 Jul 1998

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