Dual work function CMOS device
Integrated circuit field effect transisters including multilayer gate electrodes having narrow and wide conductive layers
Semiconductor device with self-aligned metal-containing gate Patent #: 6140688
ApplicationNo. 451696 filed on 11/30/1999
US Classes:257/407, With gate electrode of controlled workfunction material (e.g., low workfunction gate material)257/412, Gate electrode of refractory material (e.g., polysilicon or a silicide of a refractory or platinum group metal)257/E21.62, Manufacturing common source or drain regions between plurality of conductor-insulator-semiconductor structures (EPO)257/E21.623, Gate conductors with different gate conductor materials or different gate conductor implants, e.g., dual gate structures (EPO)257/E27.06, Field-effect transistor with insulated gate (EPO)438/585Insulated gate formation
ExaminersPrimary: Nelms, David C.
Assistant: Le, Dinh T.
Attorney, Agent or Firm
International ClassH01L 029/76
AbstractInsulated gate field effect transistors having gate electrodes with at least two layers of materials provide gate electrode work function values that are similar to those of doped polysilicon, eliminate the poly depletion effect and also substantially prevent impurity diffusion into the gate dielectric. Bi-layer stacks of relatively thick Al and thin TiN for n-channel FETs and bi-layer stacks of relatively thick Pd and thin TiN, or relatively thick Pd and thin TaN for p-channel FETs are disclosed. Varying the thickness of the thin TiN or TaN layers between a first and second critical thickness may be used to modulate the work function of the gate electrode and thereby obtain the desired trade-off between channel doping and drive currents in FETs.
Field of SearchWith gate electrode of controlled workfunction material (e.g., low workfunction gate material)
Multiple polysilicon layers
With multiple levels of polycrystalline silicon
Complementary insulated gate field effect transistors
With channel conductivity dopant same type as that of source and drain
Gate electrode of refractory material (e.g., polysilicon or a silicide of a refractory or platinum group metal)
Containing germanium, Ge
At least one layer forms a diffusion barrier
Making plural insulated gate field effect transistors having common active region
Plural gate electrodes (e.g., dual gate, etc.)
Having elevated source or drain (e.g., epitaxially formed source or drain, etc.)
Plural doping steps
Ion implantation of dopant into semiconductor region
Insulated gate formation