Analytical model for I-V characteristics of JFETs with heavily doped channels

Abstract A theoretical analysis of the I - V characteristics of junction field-effect transistors (JFETs) of types useful for electronic and optoelectronic integrated circuits, has been carried out in some detail. Attempts have been made to study the effects of various device parameters, including carrier degeneracy due to heavy doping of the channel, velocity overshoot of electrons in the channel and shortening of gate length, on the I - V characteristics of these JFETs. A new theoretical model for drift velocity v in semiconductors has been proposed for this purpose. A comparison of results from this model with those from the existing model of Trofimenkoff and with available experimental data for v attests at least to the high-field accuracy of the proposed model. Unlike almost all other models, the simple functional form of the proposed model provides it with additional advantages for application to the analytical I - V study of FETs with both uniformly and nonuniformly doped channels. Use of this model in the framework of the Lehovec-Zuleeg procedure for short-channel FETs appears to provide reasonably good results. Wherever experimental data are available, they agree at least qualitatively with results from the present model. The latter demonstrates that a very heavy doping in the p -type gate does not yield higher transconductance. A submicron gate and a heavy doping (higher than the nulled degeneracy level) in the channel are, on the other hand, necessary for higher drain saturation current and transconductance. A semiconductor alloy with the highest possible electron saturation velocity is the most suitable for high-speed JFETs.

[1]  H. Bennett.  Heavy doping effects on bandgaps, effective intrinsic carrier concentrations and carrier mobilities and lifetimes , 1985 .

[2]  P. S. Hauge,et al.  Microwave measurement of the velocity-field characteristic of GaAs , 1970 .

[3]  P.C. Chao,et al.  Experimental comparisons in the electrical performance of long and ultrashort gate length GaAs MESFET's , 1982, IEEE Electron Device Letters.

[4]  A. Reklaitis,et al.  Electron transport properties in GaAs at high electric fields , 1980 .

[5]  R. E. Nahory,et al.  Growth and characterization of liquid−phase epitaxial InxGa1−xAs , 1975 .

[6]  V. Svelto,et al.  ERRATUM: Indirect Electron Drift Velocity versus Electric Field Measurement in GaAs , 1971 .

[7]  G. E. Stillman,et al.  Electron transport in InP at high electric fields , 1983 .

[8]  Peter A. Houston,et al.  Electron drift velocity in n-GaAs at high electric fields , 1977 .

[9]  R. Barbaste,et al.  Hole mass measurement in p-type InP and GaP by submillimetre cyclotron resonance in pulsed magnetic fields , 1974 .

[10]  Jeffrey Frey,et al.  Electron velocity in Si and GaAs at very high electric fields , 1980 .

[11]  M. Ito,et al.  Monolithic integration of a photodiode and a field‐effect transistor on a GaAs substrate by molecular beam epitaxy , 1983 .

[12]  Akio Sasaki,et al.  Liquid Phase Epitaxial Growth, Electron Mobility and Maximum Drift Velocity of In1-x GaxAs (x\cong0.5) for Microwave Devices , 1977 .

[13]  S. Noor Mohammad,et al.  Theory of potential distributions in abrupt heterojunction crystalline semiconductor devices: Treatment of Schottky barriers and rectifiers , 1988 .

[14]  Maciej Bugajski,et al.  Concentration‐dependent absorption and photoluminescence of n‐type InP , 1985 .

[15]  C. Arnodo,et al.  Two-dimensional particle modeling of submicrometer gate GaAs FET's near pinchoff , 1982, IEEE Transactions on Electron Devices.

[16]  W. Knap,et al.  Polaron cyclotron resonance in n-CdTe and n-InP , 1985 .

[17]  L. Meiners,et al.  Temperature dependence of the dielectric constant of InP , 1986 .

[18]  Akio Sasaki,et al.  Electron mobility and energy gap of In0.53Ga0.47As on InP substrate , 1976 .

[19]  G. J. Rees,et al.  Heavily doped semiconductors and devices. , 1978 .

[20]  R. Zuleeg,et al.  Radiation Effects in Enhancement Mode GAAS Junction Field Effect Transistors , 1977, IEEE Transactions on Nuclear Science.

[21]  G. S. Kino,et al.  Transport Properties of GaAs , 1968 .

[22]  S. M. Sze,et al.  Physics of semiconductor devices , 1969 .

[23]  R. Zuleeg,et al.  Double-implanted GaAs complementary JFET's , 1984, IEEE Electron Device Letters.

[24]  Michael A. Littlejohn,et al.  Velocity‐field characteristics of Ga1−xInxP1−yAsy quaternary alloys , 1977 .

[25]  Sheng S. Li,et al.  The effects of heavy doping on I-V characteristics of GaAs JFET and MESFET devices , 1986 .

[26]  C. Jacoboni,et al.  A review of some charge transport properties of silicon , 1977 .

[27]  C. Cheng,et al.  High-performance InGaAs junction field-effect transistor with P/Be co-implanted gate , 1988, IEEE Electron Device Letters.

[28]  P. L. Hower,et al.  Current saturation and small-signal characteristics of GaAs field-effect transistors , 1973 .

[29]  C. Hilsum,et al.  Simple empirical relationship between mobility and carrier concentration , 1974 .

[30]  D. Gutierrez,et al.  Gigahertz logic gates based on InP-MISFET's with minimal drain current drift , 1986, IEEE Electron Device Letters.

[31]  J. Miller,et al.  A self-aligned quarter-to-half-micrometer buried-gate GaAs junction FET , 1987, IEEE Electron Device Letters.

[32]  C. Jacoboni,et al.  Electron' drift velocity and diffusivity in germanium , 1981 .

[33]  Lis K. Nanver,et al.  Characteristics of separated-gate JFETs , 1986 .

[34]  Y. Matsuoka,et al.  Influence of n+-layer-gate gap on short-channel effects of GaAs self-aligned MESFET's (SAINT) , 1983, IEEE Electron Device Letters.

[35]  R. Zuleeg,et al.  Voltage-current characteristics of GaAs J-FET's in the hot electron range☆ , 1970 .

[36]  K. Yamasaki,et al.  Determination of effective saturation velocity in n+self-aligned GaAs MESFET's with submicrometer gate lengths , 1986, IEEE Transactions on Electron Devices.

[37]  R. Zuleeg,et al.  Femtojoule high speed planar GaAs E-JFET logic , 1978, IEEE Transactions on Electron Devices.

[38]  Hiroshi Ishikawa,et al.  High-speed and high-power GaInAsP/InP junction field-effect transistor with submicron gate , 1988 .

[39]  H. P. LeBlanc,et al.  WDM experiment using 1300/1500 nm dual-wavelength LED for single-mode fibre transmission systems , 1987 .

[40]  Lis K. Nanver,et al.  Design considerations for integrated high-frequency p-channel JFETs , 1988 .