The Simox Of Soi Materials, Infrared Optical And Electrical Properties Studies

Silicon-on-insulator (SOI) has been recognized as a promising semiconductor material for integrated circuits (ICs) where high speed and low power consumption are desirable. SOI based devices have been used in harsh environments, such as high temperature and radiation electronics in automotive, space, and military applications. In addition, optical components were fabricated on SOI substrate too. As one kind of two mainstream methods to supply commercial SOI wafers, Separation by implantation of oxygen (SIMOX) plays a more important role in the field. With the development of SIMOX process, the quality control program of the SIMOX becomes more and more important in the course of the SIMOX fabrication. The thesis aims at to find the weakness of the present quality control step of the SIMOX fabrication and to look for some new methods to effectively improve the quality control methods. We have obtained some new results to deal with the key issues existing in the present application of quality control methods, the results are shown as the following.SIMOX SOI fabrication requires accurate control of the major parameters, such as wafer temperatures, oxygen ion energy and dose. The dose control, including the amount of the implanted oxygen ions and oxygen ions distribution uniformity, ultimately determines the quality of the Buried Oxide (BOX) layer. At present, the Faraday measurement of charged ion controls the thickness of the BOX layer, the source-state control does not satisfy the demanding manufacturing requirement of the BOX. The implanted oxygen dose and uniformity are also be estimated by the post-process Spectroscopic Ellipsometry (SE) measurements of the BOX thickness only after the high temperature annealing. Because the optical constants of the Si and BOX layer depend on the layer structural properties in As-implanted SIMOX, so for As-implanted SIMOX Spectroscopic Ellipsometry is not a feedback tool. The delaybetween annealing and SE measurement results in the waste of the annealing of badimplanted wafers. Reliable, high yield production of SIMOX requires a dose control with reproducibility better than 1-2%. In present work, the structural properties of As-implanted SIMOX were characterized by transmission elecrron microscopy (TEM), Rutherford back-scattering RBS and IR characterization tools. According to the structural properties of As-implanted SIMOX, we installed an optical model of As-implanted SIMOX. Base on the model of As-implanted SIMOX, the IR measurement with wavenumber in the range of 2000~5500cm~' were made to characterize the samples of As-implanted SIMOX and the best fitting process for the IR reflectra were simulated. The results showed that IR in the range of 2000~5500cm~' is sensitive to the changes of the dose of implanted oxygen ions and oxygen ions distribution uniformity in As-implanted SIMOX, even the dose deviation betweem two points was 0.7% can be detected. By the analysis and simulation of IR Spectroscopy of As-implanted SIMOX samples, before annealing step, the performance of As-implanted SIMOX can be obtained, so the annealing of bad implanted wafers were avoided.The qualities and electrical characteristics of SIMOX are of significant concern in -the technological development of the applications in electronics field. The device parameters, such as flatband voltage, fixed oxide charge and interface-trap density profile can be determined from C-V measurement on the SOI wafers. It is very crucial to study the electrical characteristic of the BOX layers of SIMOX wafers and interface states. With unique structure, the characterization of electrical properties of the SIMOX by traditional MOS method is suspect. In present study, according to the properties of SIMOX structure, Silicon On Insulator (SIS) capacitor model and Metal On Silicon On Insulator (MOSOS) capacitor model were used to measure the electrical characteristics of SIMOX. By SIS model and MOSOS model, C-V and I-V curves can be obtained. Using SIS model, by introducing a coupling factor, the existing techniques an...