Theory of the carrier‐density fluctuations in an IGFET near threshold

A three‐dimensional perturbation‐theory treatment of the carrier‐density fluctuations in the insulated‐gate field‐effect transistor (IGFET) above threshold and their effect upon the source‐drain current is presented. The fluctuations are considered to be generated by interface charge nonuniformities. It is shown that such fluctuations reduce the source‐drain current over that for a uniform device with the same average carrier density. It is found that the fluctuations increase with decreasing carrier density, that they are larger in a shallow channel than in a deep channel, and that the increase in fluctuations with decreasing carrier density is quite abrupt. The critical carrier density below which carrier‐density fluctuations are important is found to be ?1011 carriers/cm2 at 300 °K and ?1012 carriers/cm2 at 0 °K for ordinary‐device charge densities. The difference in the threshold for the onset of fluctuations at the two temperatures is attributable to the smaller amplitude of fluctuations at high temp...

[1]  F. Stern,et al.  Properties of Semiconductor Surface Inversion Layers in the Electric Quantum Limit , 1967 .

[2]  G. Declerck,et al.  Inadequacy of the classical theory of the MOS transistor operating in weak inversion , 1973 .

[3]  J. R. Brews,et al.  Carrier‐density fluctuations and the IGFET mobility near threshold , 1975 .

[4]  F. Fang,et al.  Transport Properties of Electrons in Inverted Silicon Surfaces , 1968 .

[5]  G. Declerck,et al.  The influence of surface potential fluctuations on the operation of the MOS transistor in weak inversion , 1973 .

[6]  R. Jaffee,et al.  Molecular processes on solid surfaces , 1969 .

[7]  C. Duke.  Quantum Theory of Transport in Narrow Channels , 1968 .

[8]  E. H. Nicollian,et al.  The si-sio, interface – electrical properties as determined by the metal-insulator-silicon conductance technique , 1967 .

[9]  Richard S. Muller,et al.  Carrier mobilities at weakly inverted silicon surfaces , 1974 .

[10]  F. Stern.  Self-Consistent Results for n -Type Si Inversion Layers , 1972 .

[11]  S. P. Sinitsa,et al.  Scattering Mechanisms in Inversion Channels of MIS Structures on Silicon , 1972, November 16.

[12]  E. Siggia,et al.  Properties of Electrons in Semiconductor Inversion Layers with Many Occupied Electric Subbands. I. Screening and Impurity Scattering , 1970 .

[13]  J. R. Brews,et al.  Surface Potential Fluctuations Generated by Interface Charge Inhomogeneities in MOS Devices , 1972 .

[14]  C. Herring.  Effect of Random Inhomogeneities on Electrical and Galvanomagnetic Measurements , 1960 .

[15]  C. Sah,et al.  Effects of diffusion current on characteristics of metal-oxide (insulator)-semiconductor transistors☆ , 1966 .

[16]  Effects of inhomogeneities of surface-oxide charges on the electron energy levels in a semiconductor surface-inversion layer , 1974 .

[17]  R. Troutman,et al.  Subthreshold characteristics of insulated-gate field-effect transistors , 1973 .