摘要:

Silicon, heat treated to temperatures above 1000 °C followed by a rapid quench, shows a donor activity due to the so called thermally induced donors (TID’s). In this paper it is shown that for samples treated in this way the TID effect and the behavior of the resistivity as a function of time after quenching is exactly the same as for similar samples which have been deliberately doped with iron. Hall measurements reveal the same donor levels atEv+0.40 eV in both cases indicating that unintentional Fe contamination may have taken place in the former samples during high‐temperature treatment. An extra argument in favor of the opinion that TID’s do not originate from an intrinsic effect but are due to unwanted doping is given by the fact that the entire TID effect can be eliminated by treating the samples in a H2flow containing a few percent HCl and 100 ppm O2. This mixture, which has no etching capacity, has a strong gettering effect for Fe because of the high volatility of the iron chlorides in the gas phase. Samples heated in this gas mixture and quenched rapidly remain completely free of TID’s and show no other donor activity within the accuracy of the measurements.

ISSN:0021-8979    

DOI:10.1063/1.326117

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Deep‐level transient spectroscopy by means of capacitance transients has been applied to study the characteristics of deep electron traps in low‐resistivity CdS. Thermal activation of the capacitance transients for Schottky barriers formed on three different single crystals indicates the presence of nine electron traps located between 210 and 730 meV from the conduction band. Measured trap concentrations range from low 1011to high 1014cm−3. Among the nine detected electron traps there is one with an activation energy of 210 meV which is found in the three crystals, while the traps located at 420, 470, and 730 meV from the conduction band are found in two crystals only, although not the same two crystals in all cases. Direct capture‐cross‐section measurements are performed for the level situated at 210 meV by studying the time‐dependent peak amplitude associated with trap refilling. It is shown that a time exponential variation of the trap filling process is only obtained under suitable biasing conditions. No significant variation of the capture cross sectionS∼3×10−13cm2is obtained in the explored temperature range 100–120 °K.

ISSN:0021-8979    

DOI:10.1063/1.326118

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Mobility measurements have been carried out at room temperature on phosphorus‐doped silicon samples. The desired concentration of dopant, varying in the range 1019–1020atoms/cm3, was obtained in three different ways: homogeneously during growth of the crystal, by ion implantation, and by thermal diffusion. Significant differences have been observed. A theoretical analysis, based on scattering due to dopant impurities, dislocations, and point defects, has been found to be in reasonable agreement with the results obtained from mobility measurements and from transmission electron microscopy and x‐ray analysis performed on the samples.

ISSN:0021-8979    

DOI:10.1063/1.326119

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

An analysis is given of the reflection‐loss‐limited quantum efficiency of thin‐film IV‐VI semiconductor photodiodes. The results are applied to deduction of the optimum structures for ir detector applications and are illustrated by calculations for PbTe and Pb0.8Sn0.2Te.

ISSN:0021-8979    

DOI:10.1063/1.326120

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Silicon substrates of various oxygen contents were heat treated to cause SiO2precipitation. Generation currents in pulse‐depleted MOS capacitors made on these substrates were measured. In substrates from the seed section of the crystal, SiO2precipitation began during growth of the MOS oxide, and the generation currents were very low for all the anneal cycles used. In substrates from the tail section of the crystal, where the SiO2precipitated more slowly, the generation currents decreased with anneal time and finally leveled off at a very low value. MOS capacitors were also formed on substrates in which the precipitates extended to the surface. Such MOS capacitors all showed extremely high generation currents. The conclusion that ’’internal gettering’’ by SiO2precipitates in the bulk reduces generation currents was cross‐checked with intentional copper decoration.

ISSN:0021-8979    

DOI:10.1063/1.326121

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Spectral response measurements have been made on metal‐semiconductor junction diodes of single‐crystalp‐type zinc phosphide (Zn3P2) and Al, Mg, and Be. Two different experimental configurations were used and the minority‐carrier diffusion lengths calculated using a simple theoretical treatment of the data. In one experimental mode, the light is incident on the surface of the semiconductor opposite the metal junction. The spectral response is peaked and a lower limit on the diffusion length can be calculated from the peak height and sample thickness without detailed knowledge of the optical properties of the semiconductor. In the other mode, light is incident through the metal layer and the diffusion length is calculated by analyzing the spectral response function using known values of the optical absorption coefficient. On samples for which both modes were used, the results are in good agreement. The diffusion lengths measured are in the range of 5–10 &mgr;m.

ISSN:0021-8979    

DOI:10.1063/1.326122

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A method is presented by which not only interference can be induced between two modes whose polarization directions are mutually orthogonal, i.e., between the so‐called Rayleigh‐ and Love‐type modes, but also the strength of the interference can be controlled electrically. It is shown that by applying this method electrically tunable polarization conversion can be obtained along some properly prepared acoustic surface waveguides of thin‐film type. As such waveguides, two examples are considered, each of which is composed of a properly oriented thin &agr;‐quartz film either on a fused‐quartz or on a fused‐rutile substrate, and the basic properties of the polarization conversion are calculated. The applicability of this phenomenon to some practical devices is also discussed.

ISSN:0021-8979    

DOI:10.1063/1.326123

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

We report on the open‐circuit voltageVocand the forward‐current–voltage characteristic,J=Js(expqV/nKT−1), of Schottky diodes obtained by evaporation of platinum onto hydrogenated amorphous silicon (a‐Si :H) fabricated by glow‐discharge decomposition of silane. The diode characteristics were studied as a function of several preparation parameters, namely, silane pressure, substrate temperature, silane flow rate, annealing temperature. Rectifying behavior was obtained only for substrate temperatures between 200 and 300°C. Within this constraint, the preparation parameters have only a small effect onVocbut have large influences onnandJs. The factorndecreases towards ideality (n=1) as the silane pressure decreases, as the substrate temperature increases and with annealing of the Pt contact. The corresponding decrease of the concentration of polyhydride H sites with similar variations in the preparation parameters suggests that the recombination center responsible for nonideal value ofnare associated with the polyhydride sites. We argue that the nearly constant value ofVocand therefore of the potential barrier probably originates from the crossing of the Fermi level with deep levels near the interface rather than from a previously proposed interface state. Although we were unable to use a sufficiently low temperature to choose between the thermionic emission and diffusion theories for the forward‐current‐voltage relationship, we point out that carrier injection in the metal base transistor structure favors a thermionic emission model. Assuming thermionic emission the value deduced for the Richardson constant is of the same order of magnitude as found for crystal Si Schottky barriers.

ISSN:0021-8979    

DOI:10.1063/1.326124

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The transport of electrons at high electric fields in SiO2has been calculated using an iterative solution of the path‐variable formulation of the Boltzmann transport equation. Scattering due to the polar‐optical modes and acoustic modes of the lattice are included. It is found that both the 0.153‐ and 0.063‐eV polar‐optical modes are important for scattering electrons. The electron velocity ’’saturates’’ near 1.9×107V/cm for fields below 5×106V/cm. The calculated curves are in excellent agreement with experimental data and indicate a best estimate of the polaron‐corrected conductivity mass of 1.3m0. Above 5×106V/cm, the electric field induced modifications of the carrier scattering rates cause the velocity to rise sharply. Time‐resolved polar runaway is observed with an absolute threshold in the field range of (7–8) ×106V/cm, with the runaway field increasing for short times, as may be appropriate for transport through thin oxides. Impact ionization is governed by the polar runaway, and carrier generation is observed at fields corresponding to the threshold for polar runaway.

ISSN:0021-8979    

DOI:10.1063/1.326125

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The emission of electrons from a reverse‐biassedp‐nlocated below and parallel to ann‐type emitting surface has been investigated experimentally. By sputter thinning thenlayer, followed by annealing and CS‐O treatments all in vacuum, we have been able to measure the energy distributions of emitted electrons at several differentn‐layer thicknesses, allowing direct application of a theoretical treatment due to Baraff. The surface barrier of ∼1.1 eV enables us to sample electrons having an average energy of about 3.0 eV above the conduction‐band minimum. At these energies, considerably below those studied by most others, we find the mean free path for optical phonon emission,Lp, to be 141 A˚, for ionization,Li, to be 8526 A˚, and the total attenuation length,Lo, to be 359 A˚.

ISSN:0021-8979    

DOI:10.1063/1.326126

出版商:AIP    

年代:1979

数据来源: AIP