摘要:

Observation of six electron traps in boron‐implanted, phosphorus‐doped silicon following annealing at temperatures near 400 °C is reported. Emission rate, cross section, and thermal activation energy measurements of trapped electrons are reported. Isochronal annealing information indicates that the traps are not present in the as‐implanted silicon; they are formed during heat treatment at temperatures near 400 °C. Comparison with previous studies indicated that the trap E200(0.424) [peak temperature (activation energy)] may be an oxygen and/or phosphorus complex, and that a second trap, E145(0.320), may be a phosphorus complex.

ISSN:0021-8979    

DOI:10.1063/1.335938

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Theoretical considerations which pertain to electric currents through quantum‐well structures or finite superlattices in the presence of periodic time‐dependent applied potentials are presented. The paper includes (1) a time‐dependent generalization of the time‐independent, noninteracting electron, one‐dimensional potential model of Tsu and Esaki, (2) a derivation of generalized unitarity identities which relate all of the elastic and inelastic transitions which a particle can undergo when it interacts with a periodic time‐dependent, one‐dimensional, arbitrarily shaped potential barrier, and (3) an analysis of many‐body effects which reveals additional non‐Tsu‐Esaki current terms which disappear when the time‐dependent part of the applied potential is turned off. All of the results are expressed in terms of one‐particle scattering matrices which can be computed from the ordinary single‐particle, time‐dependent Schro¨dinger equation. This work may have high‐frequency device applications.

ISSN:0021-8979    

DOI:10.1063/1.335939

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

It is shown that photoconductivity transients ina‐Si:H measured in a coplanar electrode configuration and by microwave reflection are identical. This proves that transients obtained with these techniques reflect free charge carrier kinetics where the influence of contacts can be neglected. Evidence is given that charge carrier transport is different in the surface layer and in the bulk. The influence of the temperature and the exciting light intensity on transient photoconductivity data are explained by a tentative recombination model which takes dispersive transport of holes and electrons into account.

ISSN:0021-8979    

DOI:10.1063/1.335940

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

An exact solution is given in one dimension for the electron distribution as limited by optical phonon scattering. The solution is valid for an arbitrary shape of potential energy, and current flow. Numerical results are presented for both constant field devices, and for the nonconstant fields of a typical metal‐oxide‐semiconductor‐field‐effect transistor (MOSFET) channel in silicon.

ISSN:0021-8979    

DOI:10.1063/1.335941

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

The field and time dependence of charge carriers trapping under different charge injection conditions, is studied in this work, using the dc hot electron injection technique. It is shown that the trapping characteristics converge to field‐dependent quasisaturation values. Variation of the trapping levels, due to change of the oxide field magnitude, are obtained in both directions and exhibit complete reversibility. These results, which cannot be explained by the first‐order conventional trapping model, are consistent with a dynamic trapping‐detrapping model. According to this model, quasisaturation of trapping characteristics is obtained when the trapping and detrapping processes are balanced. The occupation of the traps under steady‐state conditions is therefore field dependent. The same model also describes the generation of positive charge under high‐field injection conditions. This phenomenon is shown to be related to ionization of localized states in the SiO2forbidden gap. The implications of the dynamic model suggest the need for a reevaluation of the present characterization methods for trapping in oxide layers.

ISSN:0021-8979    

DOI:10.1063/1.335942

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

An analytic and useful form of the noise sources due to intraband scattering for the Boltzmann transport equations in the relaxation‐time approximation is obtained for nondegenerate semiconductors. It is shown that the derived noise source gives the Nyquist’s theorem.

ISSN:0021-8979    

DOI:10.1063/1.335943

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Electronic structure induced by adsorbates at the interface of Al/AlOx/Au tunnel junctions has been observed by elastic electron tunneling spectroscopy. Strong structures appearing in the tunneling spectra above ∼1 eV after exposure to I, Hg, Bi, and organohalides, have been interpreted in terms of adsorbate‐induced surface states. The spectroscopic capabilities of elastic electron tunneling spectroscopy may be useful in the area of chemical detection. In the broader sense, the observation of adsorbate‐induced unoccupied electronic states below the vacuum energy, makes elastic electron tunneling spectroscopy a potentially useful technique for the study of surfaces.

ISSN:0021-8979    

DOI:10.1063/1.335944

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

A non‐Boltzmann theory of steady‐state transport for two‐dimensional systems in a strong electric field is developed, which includes a force‐ and an energy‐balance equation. The electron temperature, impurity‐, and phonon‐limited mobilities are determined solely from these balance equations. The theory is applied to the calculation of ohmic and nonlinear transport in GaAs‐GaAlAs heterojunctions at low temperatures. Temperature‐dependent ohmic mobilities are calculated and compared with experiments. Nonlinear effects in electronic transport at low temperatures are discussed and some numerical results are presented. We also compare the present balance equations with those in the carrier temperature model.

ISSN:0021-8979    

DOI:10.1063/1.335945

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

A lead‐alloy Josephson junction with excellent uniformity of critical currents is proposed. The junction, consisting of a thin Pb‐In‐Au base electrode and an &egr;‐phase Pb‐Bi counterelectrode, is made on a thick Nb electrode. SiO openings, which define the junction area, are formed not after but before deposition of the base electrode. Using this structure, junctions can be formed free from any wet process of photolithography from the base to counter electrodes. Current‐voltage (I‐V) characteristics of series‐connected junctions are measured and uniformity of the critical currents is estimated. DespiteI‐Vcharacteristics representing large subgap current and small gap voltage, good uniformity of the critical currents is observed. The maximum to minimum spread of critical currents is ±4.1% for a 186‐junction chain with a junction area of 5 &mgr;m square. A standard deviation of 1.5% is obtained, a value about one‐third of that obtained for the conventional lead‐alloy junctions.

ISSN:0021-8979    

DOI:10.1063/1.335946

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

The elastic, piezoelectric, and dielectric constants of single‐crystal BaLaGa3O7, which belongs to the 4¯2m class of the tetragonal system, were measured. The six independent elastic constants, two piezoelectric constants, and coupling coefficients were determined using standard resonance‐antiresonance measurements and the following results were received (cijin 1011 N/m2):c11=1.78,c12=1.03,c33=1.17,c13=0.88,c44=0.39,c66=0.54,e14=0.29 C/m2,e36=0.10 C/m2,kl14=0.141, andkl36=0.055. The two dielectric constants were measured at low frequency using a three electrode configuration. The relative values of these constants were determined to be &egr;T11/&egr;0=12.7, &egr;S11/&egr;0=12.4, &egr;T33/&egr;0=9.5, &egr;S33/&egr;0=9.5.

ISSN:0021-8979    

DOI:10.1063/1.335947

出版商:AIP    

年代:1985

数据来源: AIP