ON-LINE STEREO PROCESSING FOR THE SEM.

A convenient system for the rapid extraction of three dimensional information from pairs of SEM images has been constructed, eliminating the need for time-consuming photography. Results are produced in a digestable form. Distortions inherent in the SEM record display and in the photographic system are not relevant to the system described; only those arising within the column and stage need be considered.

Application of electron beams in thermal processing of semiconductor materials and devices

Rapid and effective thermal processing methods using electron beams are described in this paper. Heating times ranging from a fraction of a second to several seconds and temperatures up to 1400°C are attainable. Applications such as the annealing of ion implanted material, both without significant dopant diffusion and with highly controlled diffusion of impurities, are described. The technique has been used successfully to activate source/drain regions for fine geometry NMOS transistors. It is shown that electron beams can produce localised heating of semiconductor substrates and a resolution of approximately 1 μm has been achieved. Electron beam heating has been applied to improving the crystalline quality of silicon-on sapphire used in CMOS device fabrication. Silicon layers with defect levels approaching bulk material have been obtained. Finally, the combination of isothermal and selective annealing is shown to have application in recrystallisation of polysilicon films on an insulating layer. The approach provides the opportunity of producing a silicon-on-insulator substrate with improved crystalline quality compared to silicon-on-sapphire at a potentially lower cost. It is suggested that rapid heating methods are expected to provide a real alternative to conventional furnace processing of semiconductor devices in the development of fabrication technology. © 1984 Benn electronics Publications Ltd, Luton.

Post-processing of vertical-cavity surface-emitting lasers for transverse mode and polarization control

The operation on how high quality single-mode operation can be readily attained on etching circles in multimode devices is discussed. Arrays of such spots can also be envisaged. Control of the polarization state is also achieved by use of deep line etches. The output filaments and beam shapes of the conventional multimode vertical cavity surface emitting lasers (VCSEL) is shown to be engineered in terms of their positions, widths, and polarizations by use of focused ion beam etching (FIBE). Several GaAs quantum well top-emitting devices with cavity diameters of 10 μm and 18 μm were investigated.

Mode control in vertical-cavity surface-emitting lasers by post-processing using focused ion-beaih etching

Single-mode emission is achieved in previously multimode gain-guided vertical-cavity surface-emitting lasers (VCSEL's) by localized modification of the mirror reflectivity using focused ion-beam etching. Reflectivity engineering is also demonstrated to suppress transverse mode emission in an oxide-confined device, reducing the spectral width from 1.2 nm to less than 0.5 nm.

Comment on 'processing and microstructure of single grain uranium-doped Y-Ba-Cu-O superconductor'

We comment on the paper by N Hari Babu et al. (2002 Supercond. Sci. Technol. 15 104-10) and point out misinterpretations of the chemical composition of U-bearing deposits observed in Y123. The observed small deposits are those of new compounds which do not contain Cu, rather than refined Y211 plus U, as stated by the authors. We further note that extensive literature, not quoted, is in disagreement by nearly an order of magnitude concerning the values of Pt and U doping at which the optimum value of Jc is obtained. Other related information, presently in the literature, which may be helpful to those working with this high temperature superconducting chemical system, is presented.