摘要:

Boron was implanted inp‐type Hg1−xCdxTe with 0.23⩽x⩽0.28. The implantation was carried out using fluences between 1×1013and 7×1016B+ cm−2and ion energies of 120 and 350 keV with the samples either at room temperature or at 80 K. For fluences of more than 1×1013B+ cm−2a saturation of the electron concentration at a level of 3×1018cm−3was obtained. No carrier freezeout was found in the implanted layers at temperatures between 10 and 300 K. Then‐type conductivity persisted after annealing for 30 min at 150 °C and disappeared after annealing at 300 and 500 °C for 30 min. The boron concentration profiles analyzed by secondary ion mass spectrometry were found to be unaffected by annealing. The results suggest that then‐type conduction is caused by implantation damage and that the implanted boron is bound in immobile complexes and does not become effective as a donor.

ISSN:0021-8979    

DOI:10.1063/1.330641

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Antimony and nitrogen have been implanted at room temperature in type Ia diamonds. From the EPR spectrum we can deduce that for small implantation doses isolated broken bonds are created. Multiple defects are created for implantation dosesD(Sb) = 2–5×1013ions/cm2andD(N) = 5×1014ions/cm2. For higher implantation doses single broken bonds prevail. Complete graphitization is obtained for high doses:D(Sb)⩾5×1015ions/cm2andD(N)⩾1016ions/cm2. In antimony doped diamonds the conductivity is only due to defects.

ISSN:0021-8979    

DOI:10.1063/1.330642

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Diffusion of Ga into quartz (crystal SiO2) and bulk‐fused silica (amorphous SiO2) was studied by neutron activation analysis. Slow and fast diffusion of Ga was observed in bulk‐fused silica, while in quartz only slow diffusion was observed. The difference in the diffusion mechanisms is discussed on the basis of the difference in porosity of the two materials. In the bulk‐fused silica, which has a lower density of 2.20 g cm−3, there are two regions with high and low densities. The higher density region is composed of cristobalite, which has the maximum distance between atomic strings of (at most) 6 A˚. The lower density region is composed of a random network of Si and O atoms, and in the network there exist many microchannels, an average diameter and the real density of which are estimated to be 17 A˚ and 7.5×1011cm−2, respectively. These microchannels act as the high‐speed diffusion paths, while the cristobalite region is the slow diffusion path. In quartz which has a density of 2.65 g cm−3, the widest interatomic spacing perpendicular tocaxis is about 5 A˚ and only the slow (bulk) diffusion can occur. The discrepancy in the diffusion coefficients of Ga reported previously by Grove and Wagner can be explained by the present model.

ISSN:0021-8979    

DOI:10.1063/1.330643

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The dynamicb1&rlarr2;b2 phase transformation of KCl was investigated in a series of plane wave experiments. Commercial Manganin gauges, used as in‐material stress gauges, recorded stress histories of the shock loaded KCl specimens. Using calibration curves for the gauge’s response under shock loading and unloading the values of theb1&rlarr2;b2 transformation stresses were determined. It was found that theb1→b2 transition is at 2.34 GPa while the reverseb2→b1 transition is at 1.61 GPa. These values are in good agreement with values given by other workers using static and dynamic methods.

ISSN:0021-8979    

DOI:10.1063/1.330644

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The piezobirefringence of GaAs has been measured over the wavelength range 3.5–10.6 &mgr;m. A small yet significant dispersion is found which is attributed to the strain dependence of the transverse optic phonon. The main contribution to the dispersion appears to be due to the strain‐induced anisotropy of the transverse effective charge. The data are in reasonably good agreement with the theory of Humphreys and Maradudin. The strain‐induced relative anisotropies of the transverse effective‐charge and the high‐frequency photoelastic constantsk∞11−k∞12andk∞44have been calculated on the basis of a two‐parameter fit to the photoelastic dispersion.

ISSN:0021-8979    

DOI:10.1063/1.330645

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The physical nature of the electrically inactive phosphorus in silicon was investigated by annealing experiments performed on laser annealed specimens doped by ion implantation up to 5×1021at/cm3. The hypothesis of point defects, which compensate or make the excess dopant electrically inactive, is contradicted by the experimental results. It was verified that phosphorus solubility corresponds to the electrically active concentration in equilibrium with the inactive dopant, and that the latter is precipitated phase. This was confirmed by transmission electron microscopy (TEM) examinations with the weak beam technique, which detected a high density of very small coherent precipitates. This method allowed us to observe particles of the same kind even on specimens thermally predeposited in conditions typical of device technology. In both cases the amount of precipitates was consistent with the inactive dopant concentration. In addition these experiments show that precipitation is associated with a high enhancement of the diffusivity of the dopant. This phenomenon can account for the plateau region of the carrier profiles after thermal predeposition.

ISSN:0021-8979    

DOI:10.1063/1.330646

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

A line‐source electron beam annealing system has been developed for directed‐energy beam processing of materials. The electron gun in this system produces a sheet beam which is focused at the sample into a line that can be swept laterally for area annealing. The system provides well‐characterized beam dwell times in the range 5 &mgr;s–2 ms, a heretofore neglected time regime. We demonstrate line‐source annealing by the system for the case of (100) epitaxial regrowth of 1250 A˚ of amorphous As‐implanted Si with dwell times as short as 150 &mgr;s. Calculations of temperature profiles and the corresponding regrowth thicknesses for solid phase epitaxy are presented for Si as a function of beam power density and dwell time. Measured power density and dwell time thresholds for layer regrowth are consistent with solid phase epitaxy of the amorphous layer. The results show the utility of the system in exploring regrowth at temperatures near the melt.

ISSN:0021-8979    

DOI:10.1063/1.330647

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

In specimens beveled for spreading resistance measurements or copper staining, the ’’on‐bevel’’ carrier distributions may be distorted from the correspondng dopant atomic distributions. The problem becomes very serious for very shallow structures in the 0.1–0.2 &mgr;m range. We have studied this problem by solving the two‐dimensional Poisson equation for some 130 cases comprising several parameters. It is found that insofar as the deviation of the on‐bevel electrical junction from the metallurgical junction is concerned, dopant profiles generally fall into two groups. Group I profiles exhibit significantly shallower on‐bevel electrical junctions than corresponding metallurgical junctions, and the situation gets precipitously worse when junctions get shallower than 0.2 &mgr;m. Profiles in this group possess gentle tails, and include gaussian, complementary error function, and exponential profiles. Group II profiles exhibit a very small ’’positive deviation’’ of the on‐bevel electrical junction from the metallurgical junction, and this deviation remains essentially unchanged as the metallurgical junction gets shallower. Profiles in this group have nearly linear or superlinear gradients in the vicinity of the metallurgical junction; a high concentration diffused arsenic emitter is an example. The ’’negative deviation’’ of the on‐bevel electrical junction from the metallurgical junction is much more serious in the case of epi with buried layers, unless the epi‐doping level is ≳1×1017atoms/cm3. Various cases of surface charge effect have also been investigated. It is found that surface charge arising from deep‐level surface states exhibits a self‐moderating effect, in contrast to a fixed amount of surface charge from shallow states.

ISSN:0021-8979    

DOI:10.1063/1.330648

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Electrical and optical properties of reactively sputtered tungsten oxide films have been investigated in relation to the oxygen concentration in sputtering atmosphere. The films with 5200–6600 A˚ thick were prepared under a constant pressure of 5×10−3Torr using a mixture of Ar and 4–50% O2. Electrical resistivity and spectral transmittance of the films formed depend extremely on the oxygen concentration in the atmosphere. The films formed in an atmosphere containing less than 13% O2are semiconductive, have a resistivity of 10−3–103&OHgr; cm, and are blue colored. The films formed in an atmosphere containing more than 16% O2are transparent and have a resistivity of 107–1011&OHgr; cm. Optical band gap of the films formed under a sputtering atmosphere containing 8–50% O2is almost constant and ranges 3.00–3.03 eV. The carrier concentration and Hall mobility of semiconductive films and the refractive index of insulating films were also measured. The presence of a critical oxygen concentration for the formation of either semiconductive or insulating films has been suggested.

ISSN:0021-8979    

DOI:10.1063/1.330649

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Rayleigh surface waves at ultrasonic frequency have been utilized to determine shear modulus variations in the vicinity of adhesive‐adherend interfaces. The measurement technique is that of acoustic critical‐angle reflectivity conducted at sequentially exposed surfaces of adhesive through the interfacial accommodation zone toward the bondline. Basic theory is presented for determining shear modulus from measured Rayleigh critical angles at adhesive surfaces. Laboratory ultrasonic Rayleigh wave apparatus and its evaluation are described. Experimental procedures for sample preparation and measurement are discussed. Results of Rayleigh critical‐angle reflectivity measurements on two different types of adhesives display a decided gradient in shear modulus through the interfacial region. Reference is made to other applications of the ultrasonic Rayleigh wave approach in studying the shear properties near the bondline of adhesive materials.

ISSN:0021-8979    

DOI:10.1063/1.330650

出版商:AIP    

年代:1982

数据来源: AIP