Abstract: The present invention relates to corona charge deposition systems that use High Voltage (HV) amplifiers for precisely controlling corona charge deposition. Some implementations, provide a corona charge deposition system that uses multiple voltage sources to maintain specified voltages applied on several electrodes to precisely control the corona current required to deposit a desired amount of charge on a sample. The HV amplifiers are able to source and sink currents to maintain stable voltages applied on control electrodes in the presence of a higher voltage applied on a needle electrode. The proposed apparatus and method of monitoring multiple signals, controlling multiple voltages, and predicting charge profile deposited on a sample can precisely control charge deposition processes.

Abstract: When a high intensity Second Harmonic Signal (SHG) probing laser is incident on a wafer surface under test, the SHG response is generally the combination of a few components: contributions from interfaces between material types (e.g., the semiconductor/dielectric interface), contributions from material non-centrosymmetric bulk regions, and/or contribution from the electric field near material interfaces. To separate the various components, SHG measurements can be performed as a function of the input probing laser polarization. Described herein are methods of acquiring an SHG versus polarization curve in a manner to expedite the measurement time.

Abstract: Apparatus is described for performing simultaneous corona deposition and surface electric field induced second harmonic (EFISH) measurements. Example designs include systems including corona guns having a focus tube for deposition of corona charge with windows therein for passage of a laser beam incident on and reflected from a sample surface. Various designs may also employ masks proximal the distal end of the focusing tube and/or proximal the sample surface. In some implementations, the apparatus is used to make ungrounded and therefore non-invasive measurements, for example, on dielectric on semiconductor such as, e.g., interface state density (Dit), flatband voltage (Vfb) and/or lifetime measurements.

Abstract: A non-invasive semiconductor technique for measuring dielectric/semiconductor interface trap density can be performed by charging the dielectric by creating charges on the top surface of the dielectric layer over the wafer using Scanning Electron Microscope (SEM) charging. This charging can induce an accumulated, a depleted and/or an inverted semiconductor surface. The states of the semiconductor surface can subsequently be measured, identified, and/or quantified using Electric Field Induced Second Harmonic generation (EFISH). From the measured/acquired EFISH versus SEM charge curve, the interface state density (Dit) can be extracted. A large working distance provides the ability to create charge and measure the Second Harmonic Generation (SHG) at the same semiconductor surface spot without the needing to move the wafer.