Electron beam induced current analysis of metal oxide silicon structures.

摘要

This thesis presents the history and the development of the scanning electron microscopy (SEM) of Metal-Oxide-Silicon structures by the Electron-Beam-Induced-Current technique (MOS/EBIC) through the year 1997. General experimental results are described which reveal the behavior of MOS capacitor structures under the influence of electron beam irradiation as well as the developments which led in a very natural way to a merging of EBIC imaging techniques and the analytical work on irradiated MOS capacitors to create the field of MOS/EBIC diagnostic imaging. Also included is a review of circuit and electromagnetic field theory as it relates to materials systems.; Specific new results and contributions of this research are also described. Although previous researchers have provided rather exhaustive lists of electrical inhomogeneities which might give rise to contrast in EBIC images of MOS capacitors, they did not provide a detailed methodology for separating the various contrast mechanisms. The conventions and techniques described herein, however, present a clear framework from which to decide the origin of MOS/EBIC contrast under accumulation, depletion/inversion and transition biasing conditions. The bias-dependent contrast behavior of breakdown sites are also described.; In addition,novel applications for using MOS/EBIC to analyze and delineate defects in semiconductor silicon are presented herein. The major finding on as-grown wafers is that B-mode failures in MOS capacitors were primarily attributed to vacancy clusters or voids of 0.1 to 0.3 {dollar}mu{dollar}m in size. It is also shown that shallow substrate and Si/SiO{dollar}sb2{dollar} interfacial defects not. detectable by conventional EBIC could be detected by MOS/EBIC, using transition bias contrast. This contrast analysis technique is described in some detail in chapters five and six. In particular, damage associated with implantation in SIMOX wafers as well as that associated with the reactive-ion-etching of pre-oxidized Si substrates is analyzed, using transmission bias techniques.