Temperature-dependent effects in field-effect measurements on hydrogenated amorphous silicon thin-film transistors

Abstract The activation energy of the source-drain current I SD in hydrogenated amorphous silicon thin-film transistors shows a correlation with the extrapolated intercept of I SD for 1/T →0 which resembles the Meyer-Neldel rule found in transport measurements on bulk samples. Previous interpretations of the Meyer-Neldel rule in field-effect experiments are discussed in detail. A unified analysis of this effect is given. The field-effect technique provides an alternative experimental method for determining the microscopic prefactor σ0 of the bulk conductivity. The accuracy of this approach is examined. It is found that 20 Ohm;−1 cm−1 < σ0 < 2000Ω−1 cm−1, the most probable value of σ0 being about 100Ω−1.cm−1. It is pointed out that knowledge of σ0 is required in order to determine the field-effect density-of-states distribution in the tail region from field-effect measurements.

[1]  P. Thomas,et al.  Influence of Electron-Phonon Coupling on Transport near a Mobility Edge , 1983 .

[2]  J. Stuke.  Problems in the understanding of electronic properties of amorphous silicon , 1987 .

[3]  R. Schropp,et al.  The determination of characteristic parameters by the temperature dependent field-effect in a-Si:H thin film transistors , 1985 .

[4]  W. Spear,et al.  Investigation of the localised state distribution in amorphous Si films , 1972 .

[5]  K. Weber,et al.  The Meyer-Neldel rule in field-effect measurements and the microscopic prefactor of the conductivity in a-Si: H , 1987 .

[6]  M. J. Powell,et al.  Defect model of charge transfer doping at a-SiNx:H/a-Si:H interfaces , 1985 .

[7]  K. Weber,et al.  Field Effect in a-Si:H Films. Influence of Annealing and Light Exposure , 1982 .

[8]  M. Tanielian,et al.  Adsorbate effects on the electrical conductance of a-Si: H , 1982 .

[9]  H. Overhof,et al.  Theoretical approaches to the interpretation of transport and optical data of amorphous semiconductors , 1987 .

[10]  J. Mares,et al.  The role of interface states in the evaluation of density of states from field effect measurements in dc-sputtered a-Si:H , 1985 .

[11]  D. Anderson,et al.  An improved field-effect analysis for the determination of the pseudogap-state density in amorphous semiconductors , 1981 .

[12]  K. Weber,et al.  Determination of the microscopic prefactor of the conductivity of a-Si:H using temperature dependent field-effect measurements , 1987 .

[13]  P. Thomas,et al.  Localization Effects in Amorphous Semiconductors , 1987 .

[14]  R. Schropp,et al.  On the quality of contacts in a-Si:H staggered electrode thin-film transistors , 1985, IEEE Transactions on Electron Devices.

[15]  P. Thomas,et al.  A Simple Scheme for Evaluating Field Effect Data , 1980 .

[16]  H. Overhof,et al.  Activated transport in amorphous semiconductors. II. Interpretation of experimental data , 1985 .

[17]  R. Schropp,et al.  Instability mechanism in hydrogenated amorphous silicon thin‐film transistors , 1987 .

[18]  I. Solomon,et al.  Space-charge-limited conduction for the determination of the midgap density of states in amorphous silicon: Theory and experiment , 1984 .

[19]  Jin Jang,et al.  Temperature dependent field effect conductance in a-Si:H☆ , 1983 .

[20]  J. Pritchard,et al.  The effect of surface states and fixed charge on the field effect conductance of amorphous silicon , 1983 .

[21]  W. Spear,et al.  A new approach to the interpretation of transport results in a-Si , 1980 .

[22]  R. Street,et al.  Recombination in plasma-deposited amorphous Si:H. Luminescence decay , 1979 .

[23]  D. Dunstan,et al.  On the application of the Meyer-Neldel rule to a-Si:H , 1983 .

[24]  Y. Muramatsu,et al.  Effect of statistical Fermi level shift on the Meyer-Neldel rule of a-Si:H conductivity , 1986 .

[25]  H. Overhof.  The Statistical Shift of the Fermi Energy and the Prefactor of the DC Conductivity in a-Si:H , 1987 .

[26]  P. L. Comber,et al.  An investigation of the conductivity prefactor in a-Si as a function of Fermi level position using the field-effect experiment , 1987 .

[27]  R. Schropp,et al.  A SELF-CONSISTENT ANALYSIS OF TEMPERATURE-DEPENDENT FIELD-EFFECT MEASUREMENTS IN HYDROGENATED AMORPHOUS-SILICON THIN-FILM TRANSISTORS , 1986 .

[28]  R. Bindemann,et al.  The ordinary and generalized Meyer-Neldel rule in a-Si:H calculated by the statistical fermi level shift , 1987 .

[29]  N. Mott.  Conduction bands in a non-crystalline environment , 1987 .