Method for detecting trap density of MOSFET (Metal Oxide Semiconductor Field Effect Transistor) gate oxide

The invention discloses a method for detecting trap density of a gate oxide layer of an MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor). The method comprises the following steps of: 1) testing threshold voltage and gate oxide layer capacitance of an MOSFET device; 2) carrying out electron beam irradiation treatment on the MOSFET, and testing the threshold voltage of the device after different irradiation doses; (3) when the threshold voltage of the device does not change along with the increase of the irradiation dose, not carrying out irradiation treatment, and recording the final threshold voltage; 4) calculating the variation of the fixed charge of the gate oxide layer according to the variation of the threshold voltage of the MOSFET before and after the electron irradiation treatment; and 5) calculating the trap density of the gate oxide layer according to the variable quantity of the fixed charges of the gate oxide layer and the area of the gate oxide layer. By utilizing the method, the trap d