Semiconductor element observation device and semiconductor element observation method

Abstract

To provide a semiconductor element observation device and a semiconductor element observation method with which it is possible to directly measure the electron state of halls and electrons, etc. generated when a diode or an LED is driven, as a temporal change of spectrum.SOLUTION: Provided is a semiconductor element observation device 1 comprising: a power supply 2 for driving a diode or a light-emitting diode; a light source 3 for irradiating the diode or the light-emitting diode in a driven state with white light; a spectrometer 4 for spectrally separating white light having passed through the diode or the light-emitting diode into light of discretionary wavelength; a first detector 5 for measuring the intensity of light of discretionary wavelength having been spectrally separated by the spectrometer 4; a second detector 6 for measuring the intensity of electroluminescence generated from the diode or the light-emitting diode by irradiation with white light; and an oscilloscope 7 for observing a temporal change of the electric signal related to the intensity of light of discretionary wavelength having been measured by the first detector 5 and the electric signal related to the intensity of electroluminescence having been measured by the second detector 6.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an observation apparatus and method for a semiconductor element for observing the electronic state of holes, electrons, etc. generated when a diode or an LED is driven. [Background technology]

[0002] In general, when a diode, a typical example of a semiconductor, operates, carrier injection from an electrode occurs, and electrical conduction takes place from there. The occurrence of carrier injection can be evaluated by measuring the current generated by application of a DC voltage to the diode, or by measuring the impedance with respect to application of an AC voltage to the diode (see, for example, Non-Patent Document 1). Also, in the recombination process in a light-emitting diode (LED), the occurrence of carrier injection can be evaluated from the measurement of the current or impedance, as well as the light emission intensity (see, for example, Non-Patent Document 2).

[0003] In some cases, useful knowledge can be obtained by evaluating the above-mentioned electrical signals. However, when undesirable processes such as carrier trap generation or element degradation occur during the operation of a semiconductor element, it is difficult to extract detailed information about carriers from the electrical transmission signal alone. Since processes such as recombination in an LED and degradation of a semiconductor element involve changes in the electronic state of the diode, it is desirable to combine them with evaluation of the electronic state of the diode. The electronic state of the diode can be evaluated, for example, by photoelectron spectroscopy. It is known that evaluation by photoelectron spectroscopy evaluates the electronic state of a diode from electronic signals due to the photoelectric effect when the diode is irradiated with ultraviolet light or X-rays. It is also known that evaluation by photoelectron spectroscopy can be combined with the operation of a semiconductor (for example, see Non-Patent Document 3).

[0004] However, in evaluation using photoelectron spectroscopy combined with the operation of a semiconductor, it is not easy to obtain a photoelectron spectroscopy signal from the operating state of the semiconductor, and furthermore, it is difficult to obtain a signal indicating the electronic level of the carriers. This is because, in this evaluation, the carriers generated when the semiconductor is operated are obtained from only a part of the entire molecule. In addition, irradiating the diode with ultraviolet light or X-rays may cause deterioration of the semiconductor element. Furthermore, in evaluation using photoelectron spectroscopy, a method for time-resolved measurement has not been fully established. Therefore, it is difficult to measure the time change in the electronic state of holes, electrons, etc. that accompanies the operation of the semiconductor element. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] HCF Martens, WFPasveer, HBBrom, JNHuiberts and PWM Blom, “Crossover from space-charge-limited to recombination-limited transport in polymer light-emitting diodes”, PHYSICAL REVIEW B, VOLUME 63, 125328 (2001). [Non-Patent Document 2] M. Takata, K. Takagi, T. Nagase, T. Kobayashi, and H. Naito, “Effects of Bimolecular Recombination on Impedance Spectra in Organic Semiconductors: Analytical Approach”, Journal of Nanoscience and Nanotechnology, Vol. 16, 3322-3326, 2016. [Non-Patent Document 3] S. Jiang, Q. Dai, J. Guo, and Y. Li, “In-situ / operando characterization techniques for organic semiconductors and devices”, Journal of Semiconductors (2022) 43(4), 04110. Summary of the Invention [Problem to be solved by the invention]

[0006] In the development of diodes and LEDs, the performance of semiconductor elements is often evaluated by measuring the current, luminance, etc. However, in order to improve the performance and degradation conditions of semiconductor elements, it is effective to also evaluate the time changes in the electronic states of holes, electrons, etc. that accompany the operation of the diode.

[0007] The present invention has been made in consideration of the above circumstances, and has an object to provide an observation apparatus and an observation method for a semiconductor element that are capable of directly measuring the electronic state of holes, electrons, etc. generated when a diode or LED is driven as a time change in spectrum. [Means for solving the problem]

[0008] The present invention has the following aspects. [1] A power source for driving a diode or a light emitting diode; a light source for irradiating a driven diode or light emitting diode with white light; a spectrometer that separates the white light transmitted through the diode or the light emitting diode into light of any wavelength; a first detector that measures the intensity of the light having the arbitrary wavelength dispersed by the spectrometer; a second detector for measuring the intensity of electroluminescence generated by the diode or the light emitting diode upon illumination with white light; an oscilloscope for observing a time change in an electrical signal related to the intensity of the light of the arbitrary wavelength measured by the first detector and a time change in an electrical signal related to the intensity of the electroluminescence measured by the second detector; An observation device for a semiconductor element comprising: [2] A power source for driving a field effect transistor; a light source that irradiates a field effect transistor in a driven state with white light; a spectroscope that separates the white light transmitted through the field effect transistor into light of an arbitrary wavelength; a detector that measures the intensity of the light of the arbitrary wavelength dispersed by the spectrometer; an oscilloscope for observing a time change in an electrical signal related to the intensity of the light of the arbitrary wavelength measured by the detector; An observation device for a semiconductor element comprising: [3] irradiating a driven diode or light emitting diode with white light; A step of splitting the white light transmitted through the diode or the light emitting diode into light of any wavelength; Measuring the intensity of the separated light of any wavelength; measuring the intensity of electroluminescence generated by the diode or the light emitting diode upon illumination with white light; Observing a time change in an electrical signal related to the measured intensity of the light of the arbitrary wavelength and a time change in an electrical signal related to the measured intensity of the electroluminescence; A method for observing a semiconductor element having the above structure. [4] irradiating a field effect transistor in a driven state with white light; A step of splitting the white light transmitted through the field effect transistor into light of any wavelength; Measuring the intensity of the separated light of any wavelength; Observing a time change in an electrical signal related to the intensity of the measured light of the arbitrary wavelength; A method for observing a semiconductor element having the above structure. Effect of the Invention

[0009] According to the present invention, it is possible to provide an apparatus and method for observing a semiconductor element that can directly measure the electronic state of holes, electrons, etc. generated when a diode or an LED is driven as a time change in spectrum. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing an observation apparatus for a semiconductor device according to an embodiment of the present invention; [Diagram 2] 1 is a schematic diagram showing an observation apparatus for a semiconductor device according to an embodiment of the present invention; [Diagram 3] 10 is a waveform diagram showing a change over time in a square wave voltage for driving a diode or a light emitting diode in Experimental Example 1. FIG. [Figure 4] 1 is a diagram showing an absorption spectrum of a semiconductor element after application of a driving voltage in Experimental Example 1. FIG. [Diagram 5] FIG. 11 is a diagram showing an absorption spectrum and an electroluminescence spectrum of a semiconductor element in a state where no voltage is applied in Experimental Example 2. [Figure 6] FIG. 13 is a diagram showing an absorption spectrum when a semiconductor element is chemically oxidized with iodine gas in Experimental Example 3. [Figure 7] FIG. 13 is a diagram showing the absorption spectrum of a semiconductor element when a voltage is applied to the semiconductor element sandwiched between calcium electrodes in Experimental Example 4. [Figure 8] 13 is a diagram showing the results of measuring the current-voltage characteristics of a semiconductor element and the relationship between the intensity of electroluminescence and the voltage in Experimental Example 5. FIG. [Figure 9] FIG. 13 is a diagram showing the results of measuring the change over time in the absorption spectrum of a semiconductor element when the voltage applied to the semiconductor element is increased from 0.8 V to 2 V in Experimental Example 6. [Figure 10] FIG. 13 is a diagram showing the results of measuring carriers generated in a semiconductor layer during operation of a field effect transistor in synchronization with gate bias application in Experimental Example 7. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] An embodiment of a semiconductor element observation apparatus and a semiconductor element observation method according to the present invention will be described. It should be noted that the present embodiment is specifically described to allow a better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified.

[0012] (1) First embodiment [Semiconductor element observation equipment] 1 is a schematic diagram showing an observation apparatus for a semiconductor device according to one embodiment of the present invention. Hereinafter, the observation apparatus for a semiconductor device according to the present embodiment may be referred to as the "observation apparatus." 1, the observation device 1 of this embodiment includes a power source 2, a light source 3, a spectrometer 4, a first detector 5, a second detector 6, and an oscilloscope 7. The observation device 1 of this embodiment preferably includes a first concave mirror 8 and a second concave mirror 9. The observation device 1 of this embodiment preferably includes a condenser lens 10.

[0013] The observation apparatus 1 of this embodiment is an apparatus for observing the electronic state of a semiconductor element 200. The semiconductor device 200 includes a diode or a light emitting diode. The semiconductor element 200 is connected to a power source 2 via a conductor 11 .

[0014] The power supply 2 is for driving the diode or light-emitting diode included in the semiconductor device 200. There are no particular limitations on the power supply 2 as long as it can generate a pulse voltage.

[0015] The light source 3 is for irradiating white light onto a diode or a light emitting diode in a driven state by application of a voltage by the power source 2. The light source 3 is not particularly limited as long as it can generate white light.

[0016] The spectroscope 4 is for separating the white light transmitted through the diode or light emitting diode in a driven state into light of any wavelength (visible light, near infrared light) by irradiating the white light. The spectroscope 4 is not particularly limited as long as it can separate the white light into light of any wavelength.

[0017] The first detector 5 is for measuring the intensity of light of an arbitrary wavelength dispersed by the spectrometer 4. The first detector 5 is not particularly limited as long as it can measure the intensity of light of an arbitrary wavelength, and may be, for example, a photodiode. The first detector 5 is connected to the oscilloscope 7 via a conductor 12. The first detector 5 also includes an amplifier, which can amplify the light of the arbitrary wavelength.

[0018] The second detector 6 is for measuring the intensity of electroluminescence generated from the diode or light-emitting diode by irradiation with white light. The second detector 6 is not particularly limited as long as it can measure the intensity of electroluminescence generated from the diode or light-emitting diode, and may be, for example, a photodiode. The second detector 6 is connected to an oscilloscope 7 via a conductor 12. The second detector 6 also includes an amplifier, which can amplify the electroluminescence.

[0019] The oscilloscope 7 is for observing the time change of the electrical signal related to the intensity of light of a given wavelength measured by the first detector 5 and the electrical signal related to the intensity of electroluminescence measured by the second detector 6. There are no particular limitations on the oscilloscope 7 as long as it is capable of observing the time change of the electrical signal.

[0020] The first concave mirror 8 is for collecting the white light generated from the light source 3 and irradiating it onto the diode or light emitting diode included in the semiconductor element 200. When the white light is irradiated onto the semiconductor element 200 using a lens, a spatial distribution of the wavelength occurs due to differences in refractive index depending on the wavelength (chromatic aberration). Therefore, by using the first concave mirror 8, the occurrence of a spatial distribution of the wavelength is suppressed.

[0021] The second concave mirror 9 is for collecting the white light transmitted through the diode or light emitting diode included in the semiconductor device 200 and making it enter the spectroscope 4 .

[0022] The condenser lens 10 is for condensing electroluminescence generated by recombination of holes and electrons in a diode or light-emitting diode due to irradiation with white light, and directing the condensed light into the second detector 6 .

[0023] Normally, the intensity of the white light generated from the light source 3 is low, so that the semiconductor element 200 is unlikely to be deteriorated by the white light. However, when the intensity of the white light is high and deterioration of the semiconductor element 200 by the white light is expected, light equal to or less than the energy gap of the semiconductor element 200 may be transmitted through the semiconductor element 200. In this case, in order to reduce the amount of white light, a light amount reducing filter such as a colored glass filter is placed between the light source 3 and the semiconductor element 200. Note that carriers and the like generated during the operation of the semiconductor element 200 usually have transition energy smaller than the energy gap of the semiconductor element 200, so that they can be observed even if a light amount reducing filter is placed. In addition, in measuring electroluminescence, visible light is cut by a light amount reducing filter placed between the light source 3 and the semiconductor element 200, and only visible light of the electroluminescence is detected by an interference filter or the like on the second detector 6 side of the semiconductor element 200.

[0024] In the observation device 1 of this embodiment, white light generated from the light source 3 is collected by the first concave mirror 8. The white light collected by the first concave mirror 8 is irradiated onto a diode or a light emitting diode included in the semiconductor element 200. The white light transmitted through the diode or the light emitting diode is collected by the second concave mirror 9. The white light collected by the second concave mirror 9 is incident on the spectroscope 4.

[0025] The spectrometer 4 separates the white light into light of a given wavelength (visible light, near-infrared light). After the spectrometer 4 separates the white light into light (or optical energy) of a given wavelength, the first detector 5 measures the intensity of the light of the given wavelength, and after amplifying the light of the given wavelength, an electrical signal of the light of the given wavelength is transmitted to the oscilloscope 7.

[0026] The first detector 5 obtains a current signal (electrical signal) proportional to the intensity of the white light transmitted through the diode or light emitting diode. The amplifier of the first detector 5 amplifies the electrical signal while converting the current into a voltage.

[0027] Electroluminescence generated from the diode or light emitting diode by irradiation with white light is collected by the collecting lens 10 and made incident on the second detector 6 .

[0028] A current signal (electrical signal) proportional to the intensity of the electroluminescence is obtained in the second detector 6. The amplifier built into the second detector 6 amplifies the electrical signal while converting the current into a voltage.

[0029] The oscilloscope 7 has a function of continuously recording and outputting the electrical signal at each time. Specifically, the signal of the transmitted light after amplified by the spectroscope 4 at each time position is continuously output on the oscilloscope. Therefore, if the wavelength sweep of the spectroscope 4 is synchronized at the same time as the start of this continuous recording, the wavelength change of the electrical signal related to the white light transmitted through the diode or light-emitting diode at each time is recorded. Also, the wavelength change of the electrical signal related to the electroluminescence generated from the diode or light-emitting diode at each time is recorded.

[0030] The semiconductor device observation apparatus 1 of this embodiment combines visible and near-infrared spectroscopy, which enables direct observation of electrons and holes generated by driving a diode or light-emitting diode, with the operation of the diode or light-emitting diode, and can observe information on changes in the electronic state that occur when the diode or light-emitting diode is operated under experimental conditions that do not cause the diode or light-emitting diode to deteriorate. Furthermore, the semiconductor device observation apparatus 1 of this embodiment combines the above-mentioned visible and near-infrared spectroscopy with an oscilloscope, so that the process in which electrons and holes are generated and recombined after the diode or light-emitting diode is driven can be directly observed as a spectral change.

[0031] [Method of observing semiconductor elements] A method for observing a semiconductor element according to one embodiment of the present invention includes the steps of irradiating a diode or light-emitting diode in an operating state with white light (hereinafter referred to as "step A1"); separating the white light transmitted through the diode or light-emitting diode into light of arbitrary wavelengths (hereinafter referred to as "step B1"); measuring the intensity of the separated light of the arbitrary wavelengths (hereinafter referred to as "step C1"); measuring the intensity of electroluminescence generated from the diode or light-emitting diode by irradiating it with white light (hereinafter referred to as "step D1"); and observing an electrical signal related to the measured intensity of the light of the arbitrary wavelength and a time change in the electrical signal related to the measured intensity of the electroluminescence (hereinafter referred to as "step E1").

[0032] Hereinafter, the observation method for a semiconductor device according to this embodiment will be described with reference to FIG.

[0033] "Process A1" In step A1, a voltage is applied by a power source 2 to a diode or a light emitting diode in a driven state, and white light is irradiated from a light source 3.

[0034] "Process B1" In step B1, the white light transmitted through a diode or a light emitting diode is split into light of a given wavelength (visible light, near infrared light) by a spectroscope 4.

[0035] "Process C1" In step C1, a current signal (electrical signal) proportional to the intensity of light of an arbitrary wavelength dispersed by the spectrometer 4 is obtained by the first detector 5, and the intensity of the electrical signal is measured by the first detector 5. In addition, an amplifier provided in the first detector 5 amplifies the electrical signal at the same time as converting the current into a voltage.

[0036] "Process D1" In step D1, a current signal (electrical signal) proportional to the intensity of electroluminescence generated from the diode or light-emitting diode by irradiating it with white light is obtained by the second detector 6, and the intensity of the electrical signal is measured by the second detector 6. In addition, an amplifier provided in the second detector 6 amplifies the electrical signal at the same time as converting the current to a voltage.

[0037] "Process E1" In step E1, the time change of an electrical signal related to the intensity of light of a given wavelength measured by the first detector 5 and the time change of an electrical signal related to the intensity of electroluminescence measured by the second detector 6 are observed by the oscilloscope 7. "Electrical signal related to the intensity of light of any wavelength" refers to a signal obtained by measuring the absorption signal generated from a diode or light-emitting diode by irradiating it with white light. By comparing the signal with the time dependence of electroluminescence intensity, the timing at which carriers are generated and their contribution to electroluminescence at that time can be evaluated.

[0038] The semiconductor device observation method of this embodiment combines visible and near-infrared spectroscopy, which enables direct observation of electrons and holes generated by driving a diode or light-emitting diode, with the operation of the diode or light-emitting diode, and can observe information on changes in the electronic state that occur when the diode or light-emitting diode is operated under experimental conditions that do not cause the diode or light-emitting diode to deteriorate. Also, the semiconductor device observation method of this embodiment combines the above-mentioned visible and near-infrared spectroscopy with observation of the time change in an electrical signal using an oscilloscope, and can directly observe the process in which electrons and holes are generated and recombined after the diode or light-emitting diode is driven as a spectral change.

[0039] (2) First embodiment [Semiconductor element observation equipment] 2 is a schematic diagram showing an observation apparatus for a semiconductor device according to one embodiment of the present invention. Hereinafter, the observation apparatus for a semiconductor device according to this embodiment may be referred to as the "observation apparatus." 2, the observation device 100 of this embodiment includes a power source 21, a light source 22, a spectrometer 23, a detector 24, and an oscilloscope 25. In addition, the observation device 100 of this embodiment preferably includes a first concave mirror 26 and a second concave mirror 26.

[0040] The observation device 100 of this embodiment is a device for observing the electronic state of a semiconductor element 300 . 2, the semiconductor element 300 includes, for example, a glass substrate 310, a gate layer 320, a transparent dielectric layer 330, and a semiconductor layer 340. In the semiconductor element 300, the gate layer 320, the transparent dielectric layer 330, and the semiconductor layer 340 are stacked in this order on the glass substrate 310. The semiconductor layer 340 includes a field effect transistor. The semiconductor element 300 is provided with a pair of electrodes 410, 420 on the semiconductor layer 340 for applying a voltage to the semiconductor layer 340. The electrodes 410, 420 are connected to the power source 21 via a conductor 28. The electrodes 410, 420 may be, for example, an electrode film made of gold.

[0041] The power supply 21 is for driving the field effect transistor included in the semiconductor layer 340. As the power supply 21, the same power supply as the power supply 2 described above can be used.

[0042] The light source 22 is for irradiating with white light the field effect transistor in a driven state by application of a voltage by the power source 21. As the light source 22, the same one as the light source 3 described above can be used.

[0043] The spectroscope 23 is for separating the white light transmitted through the field effect transistor in a driven state into light of any wavelength (visible light, near infrared light). The spectroscope 23 may be the same as the spectroscope 4 described above.

[0044] The detector 24 is for measuring the intensity of light of a given wavelength dispersed by the spectroscope 23. As the detector 24, the same detector as the first detector 5 described above can be used.

[0045] The oscilloscope 25 is for observing the time change of an electrical signal related to the intensity of light of an arbitrary wavelength measured by the detector 24. As the oscilloscope 25, one similar to the oscilloscope 7 described above can be used.

[0046] The first concave mirror 26 is for collecting the white light generated from the light source 22 and irradiating the light onto a field effect transistor included in the semiconductor layer 340 of the semiconductor element 300. As the first concave mirror 26, a mirror similar to the above-mentioned first concave mirror 8 can be used.

[0047] The second concave mirror 27 is for collecting the white light transmitted through the semiconductor element 300 and making it incident on the spectroscope 23. As the second concave mirror 27, a mirror similar to the above-mentioned second concave mirror 9 can be used.

[0048] Even in the observation device 100 of this embodiment, if the intensity of the white light is high and deterioration of the semiconductor element 300 due to the white light is expected, a light-reducing filter such as a colored glass filter may be placed between the light source 22 and the semiconductor element 300 to reduce the amount of white light.

[0049] In the observation device 100 of this embodiment, white light generated from the light source 22 is collected by the first concave mirror 26. The white light collected by the first concave mirror 26 is irradiated onto a field effect transistor included in the semiconductor layer 340 of the semiconductor element 300. The white light transmitted through the field effect transistor is collected by the second concave mirror 27. The white light collected by the second concave mirror 27 is incident on the spectroscope 23.

[0050] The spectrometer 23 separates the white light into light of a given wavelength (visible light, near-infrared light). After the spectrometer 23 separates the white light into light (or optical energy) of a given wavelength, the detector 24 measures the intensity of the light of the given wavelength, and after amplifying the light of the given wavelength, transmits an electrical signal of the light of the given wavelength to the oscilloscope 25.

[0051] The detector 24 obtains a current signal (electrical signal) proportional to the intensity of the white light transmitted through the field effect transistor. The amplifier of the detector 24 amplifies the electrical signal while converting the current into a voltage.

[0052] The oscilloscope 25 has a function of continuously recording and outputting the electrical signal at each time. Specifically, the signal of the transmitted light after amplified by the spectroscope 23 at each time position is continuously output on the oscilloscope. Therefore, if the wavelength sweep of the spectroscope 23 is synchronized at the same time as the start of this continuous recording, the wavelength change of the electrical signal related to the white light transmitted through the field effect transistor at each time is recorded. Also, the wavelength change of the electrical signal related to the electroluminescence generated from the field effect transistor at each time is recorded.

[0053] The semiconductor element observation apparatus 100 of this embodiment combines visible and near-infrared spectroscopy, which enables direct observation of electrons and holes generated by driving a field effect transistor, with the operation of the field effect transistor, and can observe information on changes in the electronic state that occur when the field effect transistor operates under experimental conditions that do not cause the field effect transistor to deteriorate. Furthermore, the semiconductor element observation apparatus 100 of this embodiment combines the above-mentioned visible and near-infrared spectroscopy with an oscilloscope, so that the process in which electrons and holes are generated and recombined after the field effect transistor is driven can be directly observed as a spectral change.

[0054] [Method of observing semiconductor elements] A method for observing a semiconductor element according to one embodiment of the present invention includes a step of irradiating a field effect transistor in an operating state with white light (hereinafter referred to as "step A2"), a step of separating the white light transmitted through the field effect transistor into light of arbitrary wavelengths (hereinafter referred to as "step B2"), a step of measuring the intensity of the separated light of the arbitrary wavelengths (hereinafter referred to as "step C2"), and a step of observing the change over time in an electrical signal related to the intensity of the measured light of the arbitrary wavelengths (hereinafter referred to as "step D2").

[0055] Hereinafter, the observation method for a semiconductor device according to this embodiment will be described with reference to FIG.

[0056] "Process A2" In step A2, a voltage is applied by a power source 21 to the field effect transistor in a driving state, and white light is irradiated from a light source 22.

[0057] "Process B2" In step B2, the white light transmitted through the diode or light emitting diode is split into light of any wavelength (visible light, near infrared light) by the spectroscope 23.

[0058] "Process C2" In step C2, a current signal (electrical signal) proportional to the intensity of light of an arbitrary wavelength dispersed by the spectrometer 23 is obtained by the detector 24, and the intensity of the electrical signal is measured by the detector 24. An amplifier provided in the detector 24 amplifies the electrical signal at the same time as converting the current into a voltage.

[0059] "Process D2" In step D2, the oscilloscope 25 observes the change over time in the electrical signal related to the intensity of light of an arbitrary wavelength measured by the detector 24.

[0060] The semiconductor device observation method of this embodiment combines visible and near-infrared spectroscopy, which enables direct observation of electrons and holes generated by driving a field-effect transistor, with the operation of the semiconductor device, and can observe information on changes in the electronic state that occur when the field-effect transistor operates under experimental conditions that do not cause the field-effect transistor to deteriorate. Also, the semiconductor device observation method of this embodiment combines the above-mentioned visible and near-infrared spectroscopy with observation of the time change in an electrical signal using an oscilloscope, and can directly observe the process in which electrons and holes are generated and recombined after the field-effect transistor is driven as a spectral change. EXAMPLES

[0061] The present invention will be described in more detail below with reference to experimental examples, but the present invention is not limited to the following experimental examples.

[0062] [Experimental Example 1] Usually, an oscilloscope records voltage with the horizontal axis being the time axis. Figure 3 is a waveform diagram showing the time change of a square wave voltage for driving a diode or a light-emitting diode. For example, consider the case where a measurement is performed to record a spectrum at the time indicated by the arrow in Figure 3. In this experimental example, the same observation device as shown in Figure 1 was used. Here, the oscilloscope has a function to continuously record and output signals at each time. Specifically, the optical signal at each time position after passing through the spectrometer and being amplified by the detector amplifier is continuously output on the oscilloscope (in this case, five output signals are output). Therefore, if the wavelength sweep of the spectrometer is synchronously started at the same time as the start of this continuous recording, the wavelength change of the signal of the light that has passed through the semiconductor element (hereinafter referred to as "transmitted light") at each time is recorded.

[0063] In Fig. 3, the leftmost arrow (1) indicates the time position immediately before the semiconductor element is driven, and the signal at this time provides information on the intensity of the transmitted light before driving. Therefore, by subtracting the signal at the position of arrow (1) from the transmitted light signals of arrows (2) to (5) other than arrow (1) in Fig. 3, it is possible to calculate the change in the intensity of the transmitted light at each time position. The intensity of transmitted light at each time and wavelength is I(t,λ), where t is time and λ is wavelength. The change ΔI(t,λ) obtained by the above subtraction is ΔI(t,λ)=I(t,λ)-I(0,λ). However, in reality, the intensity of a white lamp varies greatly depending on the wavelength, and I(t,λ) includes this contribution. Therefore, in practice, ΔI(t,λ) / I(0,λ) is calculated and normalized. Furthermore, -log 10 By multiplying by e, the absorbance change ΔOD is obtained. From the above calculations, the absorption spectrum after the application of the driving voltage shown in Figure 4 is obtained. However, in reality, the observed absorbance change is 10 -3 From 10 -4Since the amplitude is very small, about 1.6 eV, ingenuity is required to obtain the signal. Specifically, the higher the signal amplification, the less the high-speed signal can keep up, so the signal is amplified to the limit without eliminating the time change of the signal. In addition, the noise of the high-speed signal is removed using a low-pass filter such as an oscilloscope, but here too, a time constant that does not eliminate the time change of the signal is used. In the absorption spectrum after the application of the driving voltage shown in Figure 4, which was obtained by taking the above into consideration, the hole signal at 1.6 eV and the electron signal at around 2.3 eV change with time. Furthermore, the signal near 1.2 eV is the signal from the transparent electrode used as the electrode. In the spectrum after the application of the driving voltage shown in Figure 4, the signal grows with time, and the electrons and holes accumulate on the electrode with the driving time. The semiconductor element used had a transparent electrode (indium tin oxide: ITO) as the positive electrode and an aluminum electrode as the negative electrode, and an electrochemical luminescence cell made of a polymer semiconductor superyellow polyparaphenylenevinylene mixed with an ionic liquid was placed between the positive and negative electrodes as the light-emitting layer. The measurement wavelength range of the emission spectrum was 400 nm to 1000 nm, and the measurement wavelength range of the absorption spectrum was 400 nm to 900 nm.

[0064] [Experimental Example 2] The absorption spectrum and the electroluminescence spectrum of the semiconductor element were measured in the absence of applied voltage using an observation device similar to that shown in Figure 1. The results are shown in Figure 5. In FIG. 5, the dashed line indicates the absorption spectrum of the semiconductor element in the absence of applied voltage, and the solid line indicates the electroluminescence spectrum of the semiconductor element. As shown in FIG. 5, it was found that the peaks in the absorption spectrum and the electroluminescence spectrum did not match.

[0065] [Experimental Example 3] Using an observation device similar to that shown in Figure 1, the absorption spectrum was measured when a semiconductor was chemically oxidized with iodine gas. The semiconductor used was a thin film of superyellow polyparaphenylenevinylene, a polymer semiconductor. In the chemical oxidation using iodine gas, solid iodine was placed near the thin film, and the gas generated from the iodine was allowed to hit the thin film, causing an oxidation reaction. The measurement wavelength range of the absorption spectrum was set to 400 nm to 1600 nm. The results are shown in FIG. As shown in FIG. 6, it was found that the hole state occurs due to the oxidation state.

[0066] [Experimental Example 4] Using an observation device similar to that shown in FIG. 1, a voltage was applied to the semiconductor element sandwiched between calcium electrodes, and the absorption spectrum of the semiconductor element was measured. The semiconductor element used had a laminated structure of ITO / Ca / superyellow / Ca and was 7 mm×7 mm in size. The measurement wavelength range of the absorption spectrum was set to 400 nm to 1600 nm. The AC square wave voltage was modulated from 1 V to 1.5 V at 1 kHz, and the transmitted light output from the photodiode synchronized with it was amplified and measured with a lock-in amplifier. The spectrum was obtained by combining it with the wavelength change. The results are shown in Figure 7. As shown in Figure 7, when a voltage is applied while the semiconductor element is sandwiched between calcium electrodes, it is found that holes are not easily injected, and only electrons are injected, resulting in a spectrum of electron carriers.

[0067] In fact, the spectral structures of holes and electrons are similar. This is an expected result. As shown in FIG. 4, the absorption spectrum after the application of the driving voltage shows the time change of the hole signal at 1.6 eV, and the time change of the electron signal at around 2.3 eV. Therefore, in FIG. 5 to FIG. 7, the peak indicating the hole transition is on the slightly lower energy side at around 1.5 eV, and the peak indicating the electron transition is on the slightly higher energy side at around 2.4 eV. These phenomena are evidence that holes and electrons have been generated.

[0068] [Experimental Example 5] Using an observation device similar to that shown in FIG. 1, the current-voltage characteristics of the semiconductor device and the relationship between the intensity of electroluminescence and the voltage were measured. The semiconductor element used had a transparent electrode (indium tin oxide: ITO) as the positive electrode and an aluminum electrode as the negative electrode, and an electrochemical luminescence cell made of a polymer semiconductor superyellow polyparaphenylenevinylene mixed with an ionic liquid was placed between the positive and negative electrodes as the light-emitting layer. The current-voltage characteristics were obtained by varying the voltage from 0 V to 4 V in 0.1 V increments and measuring the current each time. The voltage dependence of the electroluminescence intensity was measured by a photodiode while changing the voltage, and the luminance at one of the voltage values ​​was measured by a luminance meter, and the whole was converted into a numerical value on the luminance meter. The results are shown in Figure 8. In FIG. 8, the dashed line indicates the current-voltage characteristics of the semiconductor element, and the solid line indicates the relationship between the intensity of electroluminescence and voltage. As shown in Figure 8, the current rises at 0.5 V and the intensity of the electroluminescence rises at 2.5 V. This difference occurs because in the case of current, only holes are initially injected, and at 2.5 V, electron injection also begins, and luminescent recombination begins. Therefore, below 2.5 V, it can be considered a diode in which only holes are injected.

[0069] [Experimental Example 6] Using an observation device similar to that shown in FIG. 1, the voltage applied to the semiconductor element was increased from 0.8 V to 2 V, and the change over time in the absorption spectrum of the semiconductor element was measured. The semiconductor element used had a transparent electrode (indium tin oxide: ITO) as the positive electrode and an aluminum electrode as the negative electrode, and an electrochemical luminescence cell made of a polymer semiconductor superyellow polyparaphenylenevinylene mixed with an ionic liquid was placed between the positive and negative electrodes as the light-emitting layer. A 1kHz AC square wave modulated from 0.8V to 2.0 was applied to the semiconductor element, and the change in the transmission spectrum signal was amplified and then captured on an oscilloscope to obtain a time-resolved signal. The measurement was synchronized with the wavelength change from 470nm to 1100nm to obtain a spectrum. The results are shown in Figure 9. As shown in FIG. 9, in this experimental example, it is believed that only the Hall signal was observed.

[0070] [Experimental Example 7] Using the same observation device as shown in Figure 2, we measured the carriers generated in the semiconductor layer during the operation of a field effect transistor (FET) in synchronization with the application of a gate bias. The results are shown in Figure 10. As shown in Figure 10, in addition to the hole absorption near 1.6 eV, it was found that the differential spectrum of the absorption waveform caused by the electrons in the semiconductor device being subjected to the gate electric field appears near 1.85 eV. 1st and 2nd in Figure 10 are abbreviations for first and second derivatives. [Explanation of symbols]

[0071] 1,100 Semiconductor element observation device (observation device) 2,21 Power supply 3,22 light source 4,23 Spectrometer 5 First detector 6 Second detector 7,25 Oscilloscope 8 First concave mirror 9 Second concave mirror 10 Condenser lens 24 Detector 200,300 Semiconductor elements

Claims

1. a power supply for driving the diode or light emitting diode; a light source for irradiating a driven diode or light emitting diode with white light; a spectrometer that separates the white light transmitted through the diode or the light emitting diode into light of any wavelength; a first detector that measures the intensity of the light of the arbitrary wavelength dispersed by the spectrometer; a second detector for measuring the intensity of electroluminescence generated by the diode or the light emitting diode upon illumination with white light; an oscilloscope for observing a time change of an electrical signal related to the intensity of the light of the arbitrary wavelength measured by the first detector and a time change of an electrical signal related to the intensity of the electroluminescence measured by the second detector; An observation device for a semiconductor element comprising:

2. A power source for driving the field effect transistor; a light source that irradiates a field effect transistor in a driven state with white light; a spectroscope that separates the white light transmitted through the field effect transistor into light of an arbitrary wavelength; a detector that measures the intensity of the light of the arbitrary wavelength dispersed by the spectrometer; an oscilloscope for observing a time change in an electrical signal related to the intensity of the light of the arbitrary wavelength measured by the detector; An observation device for a semiconductor element comprising:

3. illuminating a driven diode or light emitting diode with white light; A step of splitting the white light transmitted through the diode or the light emitting diode into light of any wavelength; Measuring the intensity of the separated light of any wavelength; measuring the intensity of electroluminescence generated by the diode or the light emitting diode upon illumination with white light; Observing a time change in an electrical signal related to the measured intensity of the light of the arbitrary wavelength and a time change in an electrical signal related to the measured intensity of the electroluminescence; A method for observing a semiconductor element having the above structure.

4. irradiating the field effect transistor in an active state with white light; A step of splitting the white light transmitted through the field effect transistor into light of any wavelength; Measuring the intensity of the separated light of any wavelength; Observing a time change in an electrical signal related to the intensity of the measured light of the arbitrary wavelength; A method for observing a semiconductor element having the above structure.

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