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

第二阶段SBIR奖项的主要目标是开发一种边缘场电荷分布探针（FF-CDP），该探针能够以中等到高的空间分辨率和极高的长期稳定性进行测量。 绝缘体的电气和电子特性难以通过将金属接触施加到绝缘体表面的常规方法来测量。 这项新技术显示出巨大的潜力。 它允许一个测量，无接触的最小扰动条件下，以前无法测量的基本性质的材料，特别是具有非常低的载流子浓度的材料。 该技术依赖于电场梯度中的电介质极化。 通过对介电极化的各个分量进行去卷积，可以分离体和表面贡献。 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唯一信息。 这种方法对由于结构变化、相变和产生移动的电荷的缺陷引起的体极化的变化敏感。 通过施加静电场梯度并测量作为时间函数的响应，可以评估具有长弛豫时间（秒到小时的量级）的过程。 这种过程通常是由于具有低漂移迁移率的电荷载流子，这可能在确定半导体器件的绝缘体、铁电体和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.