Charge Distribution Probe for the Measurement of Surface Charges, Internal Electric Fields and Related Fundamental Properties

第二阶段SBIR合同的主要目标是开发一种边缘场电荷分布探针（FF-CDP），能够进行中等到高空间分辨率的测量，并具有极好的长期稳定性。传统的方法是在绝缘体表面使用金属触点来测量绝缘体的电气和电子特性。这项新技术显示出巨大的潜力。它允许人们在最小扰动条件下无接触地测量以前无法测量的材料的基本性质，特别是具有极低载流子浓度的材料。该技术依赖于电场梯度中的介电极化。通过反卷积的各种成分的介电极化，体和表面的贡献可以分离。因此，获得了关于表面电荷、它们的符号和密度以及它们相关的内部场的独特信息。这种方法对由于结构变化引起的体极化变化、相变和产生移动电荷的缺陷都很敏感。通过施加静电场梯度并测量响应作为时间的函数，可以评估具有长松弛时间的过程，其数量级为秒到小时。这种过程通常是由于具有低漂移迁移率的载流子，这可能在决定绝缘体，铁电体和半导体器件的其他组件的长期稳定性方面发挥重要作用。

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.