Abstract: A method and apparatus for measuring the barrier height distribution in an insulated gate field effect transistor by intermittently illuminating a partially transparent gate electrode under bias while applying varying back gate biases to the hack gate electrode and measuring the currents conducted by the gate electrode and by the connected source and drain electrodes. Based upon the inverse Laplace transform of the ratio of the measured currents, the barrier height distribution in the transistor, including the average barrier height and the variance of the distribution of barrier heights, typically a Gaussian distribution, may be determined. A method and apparatus for adjusting the gate bias to compensate for variations in the electric field in the insulator layer due to charge generation in the insulator layer is also provided. In addition, the method and apparatus also provides for measuring the photocurrent collected under the gate electrode.

Abstract: A method and apparatus for measuring the barrier height distribution in an insulated gate field effect transistor by intermittently illuminating a partially transparent gate electrode under bias while applying varying back gate biases to the back gate electrode and measuring the currents conducted by the gate electrode and by the connected source and drain electrodes. Based upon the inverse Laplace transform of the ratio of the measured currents, the barrier height distribution in the transistor, including the average barrier height and the variance of the distribution of barrier heights, typically a Gaussian distribution, may be determined. A method and apparatus for adjusting the gate bias to compensate for variations in the electric field in the insulator layer due to charge generation in the insulator layer is also provided. In addition, the method and apparatus also provides for measuring the photocurrent collected under the gate electrode.