US 5,493,231 A · Method and apparatus for measuring the barrier height distribution in an insulated gate field effect transistor

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.

Claims29

Dependent claims

A method of measuring a barrier height distribution in an insulated gate field effect transistor having drain, gate and source electrodes formed on drain, gate and source regions of the transistor, respectively, and a back gate electrode formed on a surface of a semiconductor substrate opposite the gate region, the gate electrode being at least partially transparent, the method comprising the steps of:

electrically connecting the source and drain electrodes to one another;
applying a gate bias to the gate electrode;
generating a plurality of electrons in the semiconductor substrate;
applying a varying back gate bias to the back gate electrode while the plurality of electrons are generated, and measuring the current conducted by the gate electrode and the current conducted by the connected source and drain electrodes;
and
obtaining an inverse Laplace transform of a ratio of the measured current conducted by the gate electrode and the measured current conducted by the source and drain electrodes, to thereby determine the barrier height distribution in the transistor.

3 more elements

An apparatus for measuring a barrier height distribution in an insulated gate field effect transistor having drain, gate and source electrodes formed on drain, gate and source regions of the transistor, respectively, and a back gate electrode formed on a surface of the semiconductor substrate opposite the gate region, the gate electrode being at least partially transparent, the apparatus comprising:

means for measuring the current conducted by the gate electrode and for measuring the current conducted by the connected source and drain electrodes;
and
Laplace transform determining means, responsive to said measuring means, for determining the barrier height distribution in the transistor based upon the inverse Laplace transform of a ratio the measured current conducted by the gate electrode and the measured current conducted by the source and drain electrodes.

Dependencies are inferred from the claim text.

Method and apparatus for measuring the barrier height distribution in an insulated gate field effect transistor

Life of this patent

Method and apparatus for measuring the barrier height distribution in an insulated gate field effect transistor

Life of this patent

Abstract

Claims29