Contact Potential Difference as a Non-Destructive Testing of Steel

For steels of different grades, the effect of the chemical composition, structure, and surface etching on the contact potential difference is studied using the Kelvin probe method. It was shown experimentally that, with a change in the structure and chemical composition, the contact potential difference changes. Etching the surface of the steel with a 4% solution of nitric acid leads to a sharp decrease in the magnitude of the contact potential difference, which allows us to conclude that the value of the electron work function from the sample surface increases. The ability to control the composition and structure of the material by the Kelvin probe method is shown.

CHARACTERIZATION OF THE ELECTROPHYSICAL PROPERTIES OF SILICON-SILICON DIOXIDE INTERFACE USING PROBE ELECTROMETRY METHODS

Introduction of submicron design standards into microelectronic industry and a decrease of the gate dielectric thickness raise the importance of the analysis of microinhomogeneities in the silicon-silicon dioxide system. However, there is very little to no information on practical implementation of probe electrometry methods, and particularly scanning Kelvin probe method, in the interoperational control of real semiconductor manufacturing process. The purpose of the study was the development of methods for nondestructive testing of semiconductor wafers based on the determination of electrophysical properties of the silicon-silicon dioxide interface and their spatial distribution over wafer’s surface using non-contact probe electrometry methods.Traditional C-V curve analysis and scanning Kelvin probe method were used to characterize silicon- silicon dioxide interface. The samples under testing were silicon wafers of KEF 4.5 and KDB 12 type (orientation <100>, diameter 100 mm).Probe electrometry results revealed uniform spatial distribution of wafer’s surface potential after its preliminary rapid thermal treatment. Silicon-silicon dioxide electric potential values were also higher after treatment than before it. This potential growth correlates with the drop in interface charge density. At the same time local changes in surface potential indicate changes in surface layer structure.Probe electrometry results qualitatively reflect changes of interface charge density in silicon-silicon dioxide structure during its technological treatment. Inhomogeneities of surface potential distribution reflect inhomogeneity of damaged layer thickness and can be used as a means for localization of interface treatment defects.

Effect of Slider Bias Voltage and Humidity on Wear and Contact Potential

The effect of slider bias voltage and humidity on wear at the head/disk interface is investigated. Wear of thermal flying height control sliders is studied as a function of head/disk bias voltage, relative humidity, and heater power. The electrostatic force and the contact potential at the head/disk interface is monitored before and after head wear using the noncontact Kelvin probe method.

Study of Surface Defects in 4H-SiC Schottky Diodes Using a Scanning Kelvin Probe

In the present paper we attempt to study and explain the increased leakage currents in Schottky diodes with an integrated p-n-structure. By a scanning Kelvin probe method (vibrating capacitor) were obtained the local variations of surface contact potential difference (CPD) for the chips with large and small leakage currents. It is shown that samples with higher leakage currents have smaller surface potential barrier. The SEM investigations revealed that a critical role in increasing leakage currents play the dislocations penetrating from the substrate into the epitaxial layer.

Investigation of Additional States in the Silicon Carbide Surface after Diffusion Welding

This paper is a summary of the experimental study of deep levels in a SiC crystal lattice caused by diffusion welding (DW). Investigations were carried out by DLTS and Kelvin Probe methods. Investigations revealed that DLTS method is not applicable for identification of surface states. Research conducted by the Kelvin Probe method has shown an increase in the density of surface states after the diffusion welding from 2x1015 cm-2 to 3.5x1016 cm-2.