摘要:

This article presents a review of the state of the art of research and development on Hg1−xCdxTe ‐Hg1−yCdyTe (0≤x,y≤1) heterostructures important for applications in the modern infrared detection technique. It deals with the fundamental physical properties, epitaxial growth methods, and applications of these structures. The most important experimental results relevant to this subject are described and discussed. Following a short survey of the physical properties of Hg1−xCdxTe, the travelling heater method for growing bulk crystals of Hg1−xCdxTe has been described and compared with the epitaxial growth techniques used to prepare thin films and layered structures of this compound. Some important aspects of substrate preparation procedures related to CdTe wafers have been discussed. Then the most important problems regarding the liquid‐phase, vapor‐phase, and molecular‐beam‐epitaxy methods of Hg1−xCdxTe ‐Hg1−yCdyTe (0≤x,y≤1) heterostructures have been studied. A comprehensive discussion of technology and the parameters of different heterostructure photodiodes made of Hg1−xCdxTe with electrically passive and electrically active heterointerfaces has been presented. The review is concluded with an overview of research problems relevant to HgTe‐CdTe superlattices and the surfaces and heterointerfaces of Hg1−xCdxTe.

ISSN:0021-8979    

DOI:10.1063/1.335408

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Measurements of recombination along the tracks of 2‐MeV alpha particles and 0.7‐MeV protons in thermally grown silicon dioxide are presented. The results agree quite well with the columnar recombination model at applied fields above about 1 MV/cm if one assumes an initial Gaussian column radiusb=3.5 nm. The agreement between theory and experiment at high fields is accomplished even if the excess carriers are assumed to reach instantaneous thermal equilibrium with the lattice. At fields below 1 MV/cm, the agreement between the columnar model and the experiment is improved if one assumes that the carriers remain hot for a finite time before reaching thermal equilibrium with the lattice. The discussion of the details of the thermalization process is intended to be only rough and qualitative because the process is very difficult to model. However, the model and the experiment agree fairly well at low fields if one assumes that the carriers have an energy on the order of 1 eV for a time on the order of 10−13s. The sensitivity of the model calculations to these assumptions is discussed in some detail.

ISSN:0021-8979    

DOI:10.1063/1.335409

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Glide and climb phenomena ofa⟨100⟩ loops and dislocations in magnesium oxide have been investigated using electron microscope techniques. It has been clearly demonstrated thata⟨100⟩ dislocations could glide along ⟨100⟩ directions and from these observations the lattice friction stress was estimated to be 1.0±0.1×109dyn cm−2. From the observed shrinkage rates of loops as a function of temperature, a value of 4.5±0.3 eV for the activation energy for self‐diffusion was obtained. This study had also shown thata⟨100⟩ dislocations can split into, or be formed from, the more commonly observeda/2⟨110⟩ dislocations in magnesium oxide.

ISSN:0021-8979    

DOI:10.1063/1.335410

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Characteristics of rapid thermal and pulsed laser annealing have been investigated in boron fluoride‐ (BF+2and BF+3) ‐implanted silicon using cross‐section and plan‐view electron microscopy. The amorphous layers recrystallize by the solid‐phase‐epitaxial growth process, while the dislocation loops below the amorphous layers coarsen and evolve into a network of dislocations. The dislocations in this band getter fluorine and fluorine bubbles associated with dislocations are frequently observed. The secondary‐ion mass spectrometry techniques were used to study concomitant boron and fluorine redistributions. The as‐implanted Gaussian boron profile broadens as a function of time and temperature of annealing. However, the fluorine concentration peak is observed to be associated with dislocation band, and the peak grows with increasing time and temperature of annealing. The electrical properties were investigated using van der Pauw measurements. The electrical activation of better than 90% and good Hall mobility were observed in specimens with less than 500‐A˚ dopant‐profile broadening. In pulsed laser‐annealed specimens, the boron profile broadens both toward the surface and into the deeper regions of the crystal. However, the fluorine concentration profile exhibits a decrease in peak concentration with only a limited broadening.

ISSN:0021-8979    

DOI:10.1063/1.335411

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Amorphous silicon carbon (a‐SiC:H) films have been deposited by the glow discharge technique using SiH4and CH4gas mixtures. At high discharge powers and low deposition chamber pressures, evidence for graphitic‐type bonding in C‐deficienta‐SiC:H is found and correlations are made between the appearance of this bonding with significant changes in the electronic and structural properties. This graphitic‐type bonding can be minimized by significant H attachment to C via CHn(n=2, 3) bonding. This results ina‐SiC:H films with low gap state densities and sharp Urbach tails.

ISSN:0021-8979    

DOI:10.1063/1.335412

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

The spectral dependence of extrinsic photoresponse is reported for measurements at 8 K on ‘‘fat‐gate’’ metal‐semiconductor field‐effect transistors (MESFETs) made by silicon implantation into undoped semi‐insulating GaAs, and for similarly implanted conductive layer samples. The interest, for the field‐effect transistors (FETs), lies in any evidence concerning deep‐level flaw contributions to a space charge at the channel–substrate interface. A large photosensitivity seen in the 1.0–1.5‐eV range was identified as associated with photoionization of EL2 midgap donors, from its spectrum and photobleaching characteristics. Peaks of photoresponse were noted also at 0.54, 0.66, 0.79, and 0.89 eV. The 0.89‐eV peak can be photobleached, and is attributed to EL2+photoneutralization at sites in the interface region. The same region is postulated for the sites causing the 0.54‐eV response, postanneal complexes dervied from the ‘‘Uband’’ of implant damage states. The origins are as yet undetermined for the 0.79‐eV and the (very weak) 0.66‐eV response regions.

ISSN:0021-8979    

DOI:10.1063/1.335413

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Electron beam techniques have been used to examine the topography and composition of sputter craters formed by an indium primary ion beam from a liquid metal ion source during secondary ion mass spectrometric analysis. Secondary electron images in a scanning electron microscope revealed the crater topography but the presence of implanted In from the primary ion beam could not be detected using an energy dispersive x‐ray detector. Auger electron spectroscopy was used to detect the presence of In in the craters, and to establish the qualitative distribution of elements in and around the craters at the surface. Surface contamination of the specimens prevented quantitative interpretation. The total indium concentration distribution across the craters was measured in an electron probe microanalyzer with a crystal spectrometer. The technique can be used to measure total In in the bottom of the crater from which total sputter yield can be obtained.

ISSN:0021-8979    

DOI:10.1063/1.335414

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

The permeation of 2–22‐keV deuterons implanted into 25‐&mgr;m‐thick cold‐rolled Ni foils was studied near room temperature. The results are generally characterized by a time lag &tgr; and a steady‐state permeation rateJ. The variation of &tgr; with beam intensity and temperature indicates an average relative concentration of ∼4×10−4of saturable bulk traps of binding energy 0.26±0.01 eV, plus a larger concentration of weaker traps. At the highest energy,Jis well described by theory.

ISSN:0021-8979    

DOI:10.1063/1.335415

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Infrared reflection and transmission measurements are used to study (111)‐ and (100)‐oriented Ge samples which were implanted with sufficient fluences to produce a continuous amorphous layer. Two optical states of amorphous Ge are identified: (i) as‐implanted, amorphous state which has an infrared refractive index about 8% larger than that for single crystal Ge,nc=0.92nI; (ii) thermally stabilized amorphous state with an intermediate refractive index,nII=(0.963±0.002)nI. A shift of the fundamental absorption edge to higher energy occurs with the transition from the as‐implanted to the thermally stabilized, amorphous Ge state, but no change in the density is observed for the transition. Annealing at about 300 °C for 2 h produces the thermally stabilized state. Annealing for longer time or at higher temperatures causes measurable epitaxial regrowth. The regrowth rates and activation energies for both orientations are also determined and compared with values measured previously by another method. With the regrowth rate ∝e−Ea/kT,Ea=2.0 eV for both orientations and the regrowth rates at 350 °C are 46 A˚/min for (100) orientation and 4.0 A˚/min for (111) orientation, respectively.

ISSN:0021-8979    

DOI:10.1063/1.335416

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

First‐order Raman spectra from selected volume elements of diamonds used as anvils in a gasketed high‐pressure cell have been measured under applied load. The observed Raman profiles are interpreted on the basis of known isotropic and uniaxial stress effects in diamond‐type materials. It is demonstrated that Raman spectroscopy providesinsituexperimental information on the stress distribution within the anvils. Up to at least 300 kbar, the prominent high‐frequency edge of the Raman profile measured at the center of the diamond tip face exhibits a linear dependence on pressure within the sample volume. The application of diamond anvil Raman scattering for pressure determination is discussed.

ISSN:0021-8979    

DOI:10.1063/1.335417

出版商:AIP    

年代:1985

数据来源: AIP