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A Reflection Upon The Applicability Of Electron Beam Induced Current (Ebic) As A Sensitive Microanalytical Technique (Ppb Range) For Silicon Materials Research, Martin Kittler, Winfried Seifert

Scanning Microscopy

This paper discusses the application of electron-beam-induced current (EBIC) technique as a tool which is able to provide at least qualitative microanalytical information not available from other techniques. Three examples are given which demonstrate a sensitivity in the parts per billion (ppb) range: temperature dependence of dislocation contrast as a fingerprint of level of metal (Cu) contamination, iron determination down to 1013 atoms per cm3, and visualization of phosphorous striations in silicon grown by float-zone (FZ) method (FZ-grown Si).

Microanalytical information by EBIC is rather indirect and, usually, identification of the impurity species is not possible. Conclusions about impurity content …

Optical Studies Of Ingaas/Gaas Multiple Quantum Wells (Mqw's) And Gaas/Si Using Novel Scanning Electron Microscopy Based Techniques, D. H. Rich, H. T. Lin, Y. Tang, K. Rammohan, A. Larsson

Scanning Microscopy

The influence of defects on electron-hole plasma transport in nipi-doped in _0.2Ga_0.8As/GaAs multiple quantum wells (MQWs) has been studied using a novel technique called electron beam induced absorption modulation (EBIA) imaging. Modulation doped MQW structures exhibit large optical nonlinearities and are important for the development of all-optical spatial light modulators used in optical computing and communication. The electron-hole plasma is generated by a high-energy electron beam in a scanning electron microscope and is used as a probe to study the MQW absorption modulation induced locally by the electron beam. The influence of structural defects on the …

Strain Relaxation In Graded Ingaas And Inp Buffer Layers On Gaas (001), K. Eberl, K. Häusler, T. Shitara, Y. Kershaw, W. Sigle

Scanning Microscopy

We investigate compositionally graded In_xo≤x≤0.5Ga_1-xAs and InP buffer layers which are prepared by molecular beam epitaxy on (001) GaAs substrate. The initial In content x_o is equal to 0, 0.12, 0.18, 0.24, and 0.5 for the different samples. The In composition of the graded buffer increases linearly between x_o and 0.5 with a fixed slope of 50% In-content per μm. The idea was to combine the advantage of surface flatness in homogeneous buffer layers and the reduced density of threading dislocations on the surface for graded buffer layers. The best compromise in terms of …

Transmission Electron Microscopy, High Resolution X-Ray Diffraction And Rutherford Backscattering Study Of Strain Release In Ingaas/Gaas Buffer Layers, G. Salviati, L. Lazzarini, C. Ferrari, P. Franzosi, S. Milita, F. Romanato, M. Berti, M. Mazzer, A. V. Drigo, M. R. Bruni, M. G. Simeone, N. Gambacorti

Scanning Microscopy

Strain release and dislocation distribution in InGaAs/GaAs double heterostructures, step-graded and linear-graded buffer layers have been studied. A higher misfit dislocation density at the inner interface between the InGaAs layer and the substrate was found in all the samples. This corresponded to a strain release of the inner ternary layers much larger than predicted by equilibrium theories. The residual parallel strain of the external layers as a function of their thickness was found to follow a curve approximately of slope -0.5, in agreement with previous investigations on single InGaAs layers. This result has been interpreted as evidence that the elastic …

Dislocation Nucleation And Propagation In Semiconductor Heterostructures, D. Cherns, S. Mylonas, C. T. Chou, J. Wu, D. E. Ashenford, B. Lunn

Scanning Microscopy

This paper considers misfit dislocation nucleation and propagation in dilute magnetic semiconductor heterostructures in the CdTe-ZnTe-MnTe system. It is shown that, where the deposit is in tension, 1/2 < 110 > dislocations with inclined Burgers vectors propagate by glide along interfacial < 110 > directions and may dissociate giving intrinsic stacking faults. In cases where the deposit is in compression, 1/2 < 110 > dislocations show no evidence of dissociation and propagate by extensive cross-slip to give networks of dislocations close to interfacial < 100 > directions.

Evidence for dislocation sources in ZnTe/GaSb films is presented. ZnTe films contained stacking fault pyramids, single Frank faults and a new type of "diamond defect" …

Predicting Relaxation In Strained Epitaxial Layers, R. Beanland, D. J. Dunstan, P. J. Goodhew

Scanning Microscopy

Strained epitaxial semiconductor layers, much thicker than the critical thickness, have been used as "strain-relief" buffer layers for many years. The most successful structure developed so far dates back to the 1960's, and consists of a very thick ( ~30 μm) layer in which the misfit is gradually and continuously increased. These structures relax completely and have a sufficiently low threading dislocation density to allow a device structure to be grown on top. This process requires a very high growth rate to produce the buffer layer in a reasonable time, which is only provided by hydride vapourphase epitaxy. Recently, there …

Electron Beam Induced Current Studies Of Defect Induced Conductivity Inversion, Z. J. Radzimski, A. Buczkowski, T. Q. Zhou, C. Dubé, G. A. Rozgonyi

Scanning Microscopy

Defect induced inversion of conductivity type was studied both at the surface and at a network of interfacially confined misfit dislocations in heteroepitaxial Si(Ge) on Si structures. The inversion was achieved by controlled contamination with Au and Ni metallic impurities introduced by diffusion from backside evaporated layers. A theoretical explanation of the defect electrical activity and the inversion effect is presented, along with temperature dependent beam induced current observations.

Scanning Electron Microscopy - Electron Beam Induced Current And Deep Level Transient Spectroscopy Studies Of Gaas(In) Layers Grown By Molecular Beam Epitaxy, Y. J. Huang, Dimitris E. Ioannou, A. Iliadis

Scanning Microscopy

Electrically active defects in indium-doped (0.6%) GaAs layers grown by Molecular Beam Epitaxy (MBE) on Si-doped (≈1x10¹⁸ cm^-3) GaAs substrates have been studied by the combination of two techniques: Scanning Electron Microscope - Electron Beam Induced Current (SEM-EBIC) technique, and Deep Level Transient Spectroscopy (DLTS). The epilayers studied were three microns thick. No electrically active defects were revealed by the EBIC micrographs in the top one micron of the epilayers, whereas a large number of non-propagating misfit dislocations were observed at the epilayer/substrate interface. DLTS measurements made in the dislocation free top region of the epilayer showed …