Investigation of poly-Si/sub 1-x/Ge/sub x/ for dual-gate CMOS technology
Investigation of poly-Si/sub 1-x/Ge/sub x/ for dual-gate CMOS technology
复制标题
双栅 CMOS 技术的多晶硅/sub 1-x/Ge/sub x/研究
DOI：
10.1109/55.701432
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发表时间：
1998
影响因子：
4.9
通讯作者：
C. Hu
中科院分区：
文献类型：
--
作者：
Wen;Y. King;T. King;C. Hu
制备了x在0~0.5范围内变化的多晶硅/亚1-x/锗/亚x/栅极MOS电容器。测量了NMOS和PMOS的C-V特性。随着Ge摩尔分数的增加，PMOS器件的多晶栅耗尽效应(PDE)减小；而对于NMOS，Ge含量/SPL sim/20%的器件的多晶栅耗尽效应最小。对于PDE较小的器件，证实了较高的活性掺杂浓度和较小的栅极耗尽宽度。随着Ge含量的增加，N/sup+/膜的功函数差(/spl phi//subMS/)略有减小，而P/sup+/膜的功函数差显著减小。当P/sup+/Si/sub0.8/Ge/sub0.2/和P/sup+/Si/sub0.5/Ge/sub0.5/时，P/sup+/Si/sub0.8/Ge/sub0.2/和P/sup+/Si/sub0.5/Ge/sub0.5/P/sup+/Si/sub0.5/Ge/sub0.5/P/sup+/si/sub0.5/Ge/subx/的/SPL Phi//subMS/可以忽略不计。当Ge含量从0增加到50%时，能带隙的减少(/SPL Delta/E/subg/)也从0增加到0.26 eV。对于深亚微米双栅CMOS应用，应最小化/SPL Phi//SUB MS/的移位，以获得低且对称的V/SUB TH/以及改善的短沟道效应(SCE)。因此，Ge含量为/Spl sim/20%似乎提供了SCE和PDE之间的最佳折衷。
Poly-Si/sub 1-x/Ge/sub 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 /spl sim/20% exhibit the least PDE. Higher active dopant concentration and reduced gate-depletion width for devices featuring less PDE were confirmed. Work function difference (/spl Phi//sub MS/) was found to decrease slightly in N/sup +/ films and significantly in P/sup +/ films as Ge content increases. The shift in /spl Phi//sub MS/ for N/sup +/ poly-Si/sub 1-x/Ge/sub x/ is negligible while it is -0.13 V for P/sup +/Si/sub 0.8/Ge/sub 0.2/ and -0.32 V for P/sup +/Si/sub 0.5/Ge/sub 0.5/. The reduction in energy bandgap (/spl Delta/E/sub 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 /spl Phi//sub MS/ should be minimized for low and symmetrical V/sub th/ as well as improved short-channel effect (SCE). A Ge content of /spl sim/20% therefore seems to offer the best tradeoff between SCE and PDE.