SBIR-STTR Award

The electric and electronic properties of insulators are diffic6lt to measure by conventional methods which require metal contacts at the insulator surfaces. A new technique makes it possible to determine contact-free, previously unmeasurable fundamental properties of insulating and semiconducting materials.,The technique consists of measuring the dielectric polarization in an electric field gradient. By deconvoluting the various components of the dielectric polarization, bulk and surface contributions can be separated. Thus, unique information is obtained about surface charges, their sign and density as well as their associated internal field. The method is also highly sensitive to changes in the bulk polarization such as may be caused by the dissociation of defects and generation of mobile charges. By applying a static electric field gradient and measuring the response as a function of time, processes with long relaxation times, of the order of seconds to hours, can be evaluated. Such processes may be due to charge carriers with very low drift mobilities which, however, may play an important part in determining the long-term stability of electronic devices or ferroelectrics. The objective of the research is to develop a Charge Distribution Probe which performs measurements with high spatial resolution and determines the electronic properties of thin insulator layers.The potential commercial application as described by the awardee: Measurements with the Charge Distribution Probe provide fundamentally new information about dielectric materials that are of great interest to the electronics and semiconductor industry. It is expected that this novel technique will find widespread application in research and development laboratories and that it may become a standard laboratory method for the characterization of dielectrics.

The main objective of the Phase II SBIR award is to develop a Fringe Field Charge Distribution Probe (FF-CDP) that is capable of performing measurements with moderate to high spatial resolution and extremely good long-term stability. Electric and electronic properties of insulators are difficult to measure by conventional methods which apply metal contacts to the insulator surfaces. This new technique has shown great potential. It allows one to measure, contact-free under minimum perturbation conditions, previously unmeasureable fundamental properties of materials, especially of materials with very low charge carrier concentrations. The technique relies on the dielectric polarization in an electric field gradient. By deconvoluting the various components of the dielectric polarization, bulk and surface contributions can be separated. Thus, unique information is obtained about surface charges, their sign and density as well as their associated internal fields. This method is sensitive to changes in the bulk polarization, due to structural changes, to phase transitions, and to defects that generate mobile charges. By applying a static electric field gradient and measuring the response as function of time, processes with long relaxation times, of the order of seconds to hours, can be assessed. Such processes are often due to charge carriers with low drift mobilities, which may play an important part in determining the long-term stability of insulators, ferroelectrics and other components of semiconductor devices.