Analysis of the impact of dislocation distribution on the breakdown voltage of GaAs-based power varactor diodes

A synchrotron x-ray topography analysis of the impact of the distribution of defects/dislocations on the electrical performance of GaAs power varactor diodes was carried out. Diodes fabricated on or near Liquid Encapsulated Czochralski cellular dislocation networks in the substrate, which are also known to be rich in As precipitates near these cell walls, were observed to have reduced breakdown voltages (VBR). This is consistent with the possibility that the presence of space-charge cylinders surrounding these dislocations gives rise to reduced VBR if they thread a p-n junction; it is also in accord with the possibility that the As precipitates themselves can act as sites for local field enhancement, thus promoting premature avalanche breakdown

Synchrotron X-ray topographic study of strain in silicon wafers with integrated circuits

Section topographs made with synchrotron radiation show the strain field below the surface of silicon wafers which have gone through a process for integrated circuits. The contrast observed is a series of curved lines starting at one edge of an oxide layer and ending at its other edge. The strain is also calculated using the finite-element method. Electrical measurements such as the threshold voltage of a transistor are made in order to find the influence of the strain on the device performance and yield

Simultaneous determination of hydride- and non-hydride-forming elements by inductively coupled plasma optical emission spectrometry

This report surveys the historical development of dual-mode sample-introduction systems used with inductively coupled plasma optical emission spectrometry for the simultaneous determination of hydride- and non-hydride-forming elements by means of chemical hydride generation (HG) and pneumatic nebulization (PN), respectively. We highlight various aspects of this multi-element analysis approach, including the design of systems for simultaneous HG and PN, selection of (compromised) working conditions and their effect on analytical figures of merit, and applications to the analysis of real samples. We also highlight spectral and non-spectral interferences encountered during such operations.Peer reviewed: YesNRC publication: Ye