| 摘要 |
PROBLEM TO BE SOLVED: To provide evaluation method by which a stable result of measurement of an interface state density can be obtained even when an SOI layer is an ultra-thin SOI substrate.SOLUTION: A method for evaluating an SOI substrate by Pseudo-MOSFET method concerning the interface property of an SOI layer and a BOX layer of the SOI substrate after execution of HF processing on the SOI substrate comprises the steps of: forming a source electrode and a drain electrode on a surface of the SOI substrate, and a gate electrode on the backside of the SOI substrate; and measuring a drain current with voltages applied across the source and drain electrodes, and to the gate electrode respectively. In the drain current measuring step, in a subthreshold region where the drain current changes largely, the gate voltage applied to the gate electrode is raised at predetermined intervals, and the interface state density of the SOI substrate is measured in a length of time after HF processing in each interval, during which a quantity of change in drain current value never becomes negative.SELECTED DRAWING: Figure 6 |
