Technique of Control of the Gate Dielectric of MIS Structures Based on High-Field Charge Injection

摘要

A new method is proposed for studying the charge characteristics and control of quality of thin dielectric films of MIS structures based on a modification of the method of high-field injection of a charge into a dielectric in an increasing current mode. The technique is based on applying to the investigated MIS structure an increasing current stress, in which, in addition to the parameters characterizing the breakdown of the dielectric, the changes in its charge state are monitored. For this purpose, at injection current densities where changes in the charge state of the MIS structure become noticeable, before switching the current to a step with a larger current value, a short-term switching to the injection mode by measuring the current level ( J _( m )) is carried out. The current density J _( m )is selected from the condition that there should be no noticeable change in the charge state of the dielectric, and switching to the measuring mode should not have a noticeable effect on the test process. As a result, it is possible to obtain the dependence of the voltage change across the MIS structure on time or the value of the injected charge at a constant fixed value of the measuring injection current J _( m )over the entire range of exposure to increasing current stress. From these dependences, it is possible to determine the main parameters characterizing the charge processes occurring in the MIS structure during high-field injection of electrons and determining the degradation phenomena observed in the film of the gate dielectric.