Semiconductor Device and Method for Evaluating Semiconductor Device
First Claim
1. An evaluation method for a semiconductor device comprising the steps of:
- starting to apply a voltage between a first electrode and a second electrode at a time T0 so that a current flows in an oxide semiconductor layer electrically connected to the first electrode and the second electrode;
irradiating the oxide semiconductor layer with light having an energy higher than an energy gap of the oxide semiconductor layer, wherein the irradiating step starts at a time T1 and stops at a time T2;
comparing a value of a current flowing between the first electrode and the second electrode at a time T3 with a maximum value of a current flowing between the first electrode and the second electrode between the time T1 and the time T2; and
comparing a value of a current flowing between the first electrode and the second electrode at a time T4 with the maximum value of the current flowing between the first electrode and the second electrode between the time T1 and the time T2; and
stopping to apply the voltage between the first electrode and the second at time T5,wherein the time T1 is after the time T0,wherein the time T3 is after a period of greater than or equal to 1 second and less than or equal to 15 seconds from the time T1 and before the time T2,wherein the time T4 is after a period of greater than or equal to 1 second and less than or equal to 15 seconds from the time T2, andwherein the time T5 is after the time T4.
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Accused Products
Abstract
A semiconductor layer with a low density of trap states is provided. A transistor with stable electrical characteristics is provided. A transistor having high field-effect mobility is provided. A semiconductor device including the transistor is provided. A method for evaluating a semiconductor layer is provided. A method for evaluating a transistor is provided. A method for evaluating a semiconductor device is provided. Provided is, for example, a semiconductor layer with a low defect density which can be used for a channel formation region of a transistor, a transistor including a semiconductor layer with a low defect density in a channel formation region, or a semiconductor device including the transistor.
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Citations
17 Claims
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1. An evaluation method for a semiconductor device comprising the steps of:
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starting to apply a voltage between a first electrode and a second electrode at a time T0 so that a current flows in an oxide semiconductor layer electrically connected to the first electrode and the second electrode; irradiating the oxide semiconductor layer with light having an energy higher than an energy gap of the oxide semiconductor layer, wherein the irradiating step starts at a time T1 and stops at a time T2; comparing a value of a current flowing between the first electrode and the second electrode at a time T3 with a maximum value of a current flowing between the first electrode and the second electrode between the time T1 and the time T2; and comparing a value of a current flowing between the first electrode and the second electrode at a time T4 with the maximum value of the current flowing between the first electrode and the second electrode between the time T1 and the time T2; and stopping to apply the voltage between the first electrode and the second at time T5, wherein the time T1 is after the time T0, wherein the time T3 is after a period of greater than or equal to 1 second and less than or equal to 15 seconds from the time T1 and before the time T2, wherein the time T4 is after a period of greater than or equal to 1 second and less than or equal to 15 seconds from the time T2, and wherein the time T5 is after the time T4. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A semiconductor device comprising:
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a transistor including an oxide semiconductor layer in a channel formation region, the oxide semiconductor layer being electrically connected to a first electrode and a second electrode, wherein, while a voltage is applied between the first electrode and the second electrode, the oxide semiconductor layer begins to be irradiated with light having a peak intensity in a wavelength range of 340 nm to 360 nm and an intensity of 3 mW/cm2 at a temperature of 25°
C. at a time T0 and irradiation is stopped at a time T1,wherein a value of a current flowing between the first electrode and the second electrode at a time T2 is greater than or equal to 70% and less than 100% of a maximum value of a current flowing between the first electrode and the second electrode between the time T0 and the time T1, wherein a value of a current flowing between the first electrode and the second electrode at a time T3 is greater than or equal to 5% and less than 100% of the maximum value of the current flowing between the first electrode and the second electrode between the time T0 and the time T1, wherein the time T2 is after a period of greater than or equal to 1 second and less than or equal to 15 seconds from the time T0 and before the time T1, and wherein the time T3 is after a period of greater than or equal to 1 second and less than or equal to 15 seconds from the time T1. - View Dependent Claims (12, 13, 14, 15, 16)
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17. An evaluation method for a semiconductor device comprising the steps of:
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starting to apply a voltage between a first electrode and a second electrode at a time T0 so that a current flows in an oxide semiconductor layer electrically connected to the first electrode and the second electrode; irradiating the oxide semiconductor layer with light having an energy higher than an energy gap of the oxide semiconductor layer, wherein the irradiating step starts at a time T1 and stops at a time T2; comparing a value of a current flowing between the first electrode and the second electrode at a time T3 with a maximum value of a current flowing between the first electrode and the second electrode between the time T1 and the time T2; and comparing a value of a current flowing between the first electrode and the second electrode at a time T4 with the maximum value of the current flowing between the first electrode and the second electrode between the time T1 and the time T2; and stopping to apply the voltage between the first electrode and the second at time T5, wherein the time T1 is after the time T0, wherein the time T3 is between the time T1 and the time T2, wherein the time T4 is after a period of greater than or equal to 1 second and less than or equal to 15 seconds from the time T2, and wherein the time T5 is after the time T4.
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Specification