Method of evaluating semiconductor device and apparatus for evaluating semiconductor device
AssigneesFuji Electric Co., Ltd., National Institute of Advanced Industrial Science and Technology
InventorsMitsuru Sometani, Manabu Takei, Shinsuke Harada
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Abstract
A method of evaluating a semiconductor device having an insulated gate formed of a metal-oxide film semiconductor. The semiconductor device has a high potential side and a low potential side, and a threshold voltage that is a minimum voltage for forming a conducting path between the high and low potential sides. The method includes determining a variation of the threshold voltage at turn-on of the semiconductor device by continuously applying an alternating current (AC) voltage to the gate of the semiconductor device, a maximum voltage of the AC voltage being equal to or higher than the threshold voltage of the semiconductor device.
Claims15
A method of evaluating a semiconductor device having an insulated gate formed of a metal-oxide film semiconductor, the semiconductor device having a high potential side and a low potential side, and a threshold voltage that is a minimum voltage for forming a conducting path between the high and low potential sides, the method comprising:
- determining a variation of the threshold voltage at turn-on of the semiconductor device by continuously applying an alternating current (AC) voltage to the gate of the semiconductor device, including
- applying a constant voltage between the high potential side and the low potential side of the semiconductor device while continuously applying the AC voltage to the gate of the semiconductor device,
- measuring a change of an electric current flowing from the high potential side to the low potential side of the semiconductor device in a time period during which the AC voltage is applied, and
- obtaining the variation of the threshold voltage at the turn-on of the semiconductor device using the measured change of the electric current,
- a maximum voltage of the AC voltage being equal to or higher than the threshold voltage of the semiconductor device, a minimum voltage of the AC voltage being less than the threshold voltage of the semiconductor device, and the constant voltage being set less than a difference between the maximum voltage of the AC voltage and the threshold voltage.
A method of evaluating a semiconductor device having an insulated gate formed of a metal-oxide film semiconductor, the semiconductor device having a high potential side and a low potential side, and a threshold voltage that is a minimum voltage for forming a conducting path between the high and low potential sides, the method comprising:
- determining a variation of the threshold voltage at turn-on of the semiconductor device by continuously applying an alternating current (AC) voltage to the gate of the semiconductor device, including
- applying a constant voltage between the high potential side and the low potential side of the semiconductor device while continuously applying the AC voltage to the gate of the semiconductor device,
- measuring a change of an electric current flowing from the high potential side to the low potential side of the semiconductor device in a time period during which the AC voltage is applied, and
- obtaining the variation of the threshold voltage at the turn-on of the semiconductor device using the measured change of the electric current,
- a maximum voltage of the AC voltage being equal to or higher than the threshold voltage of the semiconductor device, a minimum voltage of the AC voltage being less than the threshold voltage of the semiconductor device,
- wherein the obtaining the variation of the threshold voltage includes obtaining the variation of the threshold voltage based on a product of the measured change of electric current and an inverse of an ON time ratio, the ON time ratio being a ratio of an ON time period, during which the applied AC voltage is equal to or higher than the threshold voltage of the semiconductor device, to the time period during which the AC voltage is applied.
A device for evaluating a semiconductor device having an insulated gate formed of a metal-oxide film semiconductor, the semiconductor device having a high potential side and a low potential side, and a threshold voltage that is a minimum voltage for forming a conducting path between the high and low potential sides, the device comprising:
- a voltage source connected to the gate of the semiconductor device, the voltage source being configured to continuously apply an alternating current (AC) voltage, a maximum voltage of which is equal to or higher than the threshold voltage of the semiconductor device, to the gate of the semiconductor device at turn-on of the semiconductor device, so as to determine a variation of the threshold voltage at the turn-on of the semiconductor device, and
- a constant-voltage source connected to the high potential side of the semiconductor device, the constant-voltage source being configured
- to apply a constant voltage between the high and low potential sides of the semiconductor device while the voltage source continuously applies the AC voltage to the gate of the semiconductor device, and
- to measure a change of an electric current flowing from the high potential side to the low potential side of the semiconductor device in a time period during which the AC voltage is applied, so that the variation of the threshold voltage is determinable using the measured change of the electric current,
- wherein the constant-voltage source is configured to supply, as the constant voltage, a voltage less than a difference between the maximum voltage of the AC voltage and the threshold voltage.
Dependencies are inferred from the claim text.