Injection of Charge from Surface Traps into Films with Deep Bulk Traps

In many cases the profile of an open circuit TSC in Teflon ® FEP shows two well defined peaks. The first is usually interpreted as due to charge injection from thermally activated surface traps into bulk traps and the second one, occurring at higher temperatures, as charge emission from these volume traps. Extending a calculation done by Kanazawa and Batra [1] a theoretical analysis for the first peak is carried out relating the surface voltage and the total charge in the sample as a function of two parameters: the initial Schubweg and the fraction of charge injected into the sample. The heat pulse technique, giving both the surface potential and the charge in the sample is suitable to verify the theory experimentally.