JP2000164663A - Semiconductor evaluating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor evaluating apparatus, which measures and evaluates at high resolution a fine structure such as p-n junction position of a semiconductor and diffusion distance of minor carrier using a proximity field interaction. SOLUTION: For a semiconductor evaluating device 1, a sample 14 which is a semiconductor device is placed on a PZT stage 2, the sample 14 is applied with a bias voltage from a bias circuit 13, while a probe 3 is applied with the vibration at resonance frequency for the probe 3 in the horizontal direction by a vibrator mechanism 4, and the PZT stage 2 is adjusted in position in three directions (XYZ) by a personal computer 8, while the amplitude of the probe 3 is being detected with a laser diode 6 and a photodiode 7. In the probe 3, with the introduction of laser beam resonant with vibration from a semiconductor laser 9, an evernescent field is produced from a minute opening at its tip end and the proximity field interaction between the sample 14 and the probe 3 excites a minor carrier at the sample 14, then the semiconductor evaluating device 1 detects changes in optical excitation current for the evaluation of the sample 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor evaluation apparatus, and more particularly, to a semiconductor evaluation apparatus that measures and evaluates a fine structure of a semiconductor device and its defects at high resolution.

[0002]

2. Description of the Related Art In a semiconductor device, if there is a minute defect due to dielectric breakdown or electric leakage inside the device,
Reduce the reliability of semiconductor devices.

[0003] For example, when a semiconductor device is operated by applying an electric field, if the semiconductor device has a defect, a light emission phenomenon due to the defect, a light emission phenomenon due to hot electrons, latch-up and the like may occur. This hot electron is applied to a field effect transistor (FET: Fiel
d Effect Transistor) has the problem of damaging the insulating film and deteriorating its electrical characteristics. Also, CMOS
When the latch-up phenomenon occurs in the element, a current continues to flow from the power supply terminal to the contact terminal, and there is a problem that its electric characteristics are deteriorated.

[0004] Such defects of the semiconductor device are caused by various causes such as the thickness of the insulating film used in the device, the flatness of the surface, contamination by impurities, and changes in the internal structure due to stress.

Therefore, by detecting the defect location of the semiconductor device with high resolution and clarifying the cause of the defect, it is necessary to change the design policy and improve the method of manufacturing the semiconductor device in order to improve the reliability of the semiconductor device. It can be carried out.

[0006] Elucidating in which location of a semiconductor device a light-emitting phenomenon occurs during operation is a very important factor for evaluating the characteristics and reliability of the semiconductor device. It is also an effective means for elucidating the defect of a semiconductor device and its cause.

Therefore, conventionally, the above-mentioned light-emitting phenomenon is measured by operating a semiconductor device, condensing light generated in the device with a microscope, and then dispersing the light using a monochromator or using a filter to obtain a photomultiplier. Tube or CCD
(Charge Coupled Device) is observed by measuring the amount of light with a light receiving element.

However, as the size of semiconductor devices has been reduced to half micron and further to sub-half micron, it has become difficult to evaluate by direct observation with actual size devices. The light emission phenomenon is estimated by a method such as computer simulation based on electrical characteristics.

Conventionally, an electron beam is applied to a pn junction using a scanning electron microscope, and a light emission phenomenon is observed using an electron excitation current (EBIC) flowing between the pn junctions. I have.

[0010]

However, if a semiconductor device is evaluated using such a conventional method of observing a light emitting phenomenon, it is not possible to appropriately evaluate a semiconductor device that has been increasingly integrated in recent years. There was a problem.

In other words, in recent years, the miniaturization of the minimum line width of the wiring of a semiconductor device has been advanced with the improvement of the degree of integration. For example, in a 16 Mbit memory, the minimum line width is about 0.5 μm. Further, recently, a 1-Gbit memory has appeared, and such a 1-Gbit memory is about 0.1 μm. Therefore, in order to detect a light emission phenomenon due to hot carriers or latch-up and evaluate a semiconductor device, observation measurement in a minute region of 0.1 μm or less is required.

However, in the conventional technique of observing with a microscope using a conventional optical system, it is impossible in principle to measure a region below the diffraction limit of light.
Its resolution is at most about 1 μm (IEEE
Transactions on electrondevices Vol. 37,
No. 9 1990, 2080).

The method using a scanning electron microscope is described in p.
Although the junction position of the −n junction can be directly measured, its resolution is about 1 μm due to contamination of the sample and limitations in the performance of the scanning electron microscope.

Therefore, the above conventional method for observing the light emission phenomenon is insufficient in terms of resolution to evaluate a semiconductor device with a high density, and a high-resolution measurement method in a finer area is required. Have been.

Therefore, a method and apparatus for evaluating a semiconductor material using a near-field optical microscope have been proposed (see Japanese Patent Application Laid-Open No. 9-82771). The method and the apparatus for evaluating a semiconductor material energize a semiconductor material that is a sample on a sample stage and detect near-field light generated from the energized semiconductor material. A probe to be captured, a vibration mechanism for vibrating the probe in a direction perpendicular to the sample surface, a displacement detection mechanism for detecting a change in amplitude or frequency of vibration of the probe to control a gap with the sample surface, and a probe. And has a light detection system that splits and detects the light captured in accordance with the vibration of the probe.

However, in the actual light emission phenomenon, all light emission components are scattered.
There is a problem that it is not possible to detect only the near-field component of the light emission phenomenon, and it is not possible to appropriately evaluate a semiconductor device.

Therefore, according to the present invention, the tip is formed close to the semiconductor device mounted on the mounting table, the tip is formed to have a size equal to or smaller than a predetermined light wavelength, and a minute opening is formed at the tip. While changing the relative position between the probe and the semiconductor device formed with, the near-field interaction between the semiconductor device and the probe excites minority carriers in the semiconductor device, and detects the change in the photoexcitation current,
To provide a semiconductor evaluation device capable of measuring a pn junction position and a minority carrier diffusion length of a semiconductor device with high resolution by evaluating the semiconductor device, and more accurately evaluating the semiconductor device. It is an object.

According to a second aspect of the present invention, the probe is vibrated in the horizontal direction at the resonance frequency of the probe, the vibration of the vibrating probe is detected, and the probe and the semiconductor device are connected based on the detection result. By controlling the position of the probe, the distance between the probe and the semiconductor device is more precisely controlled, and the probe is vibrated only at the resonance frequency, so that the pn junction position of the semiconductor device and the diffusion length of minority carriers can be more improved. It is an object of the present invention to provide a semiconductor evaluation apparatus capable of performing measurement with a higher resolution and a simple configuration, and more accurately and inexpensively evaluating a semiconductor device.

According to a third aspect of the present invention, a semiconductor device is evaluated by detecting a change in a photoexcitation current and detecting a change in a light emission phenomenon due to a near-field interaction between the semiconductor device and the probe with the probe. A semiconductor evaluation that can measure a pn junction position and a diffusion length of minority carriers of a semiconductor device at a high resolution while measuring a defect position and a defect distribution of the semiconductor device with high resolution. It is intended to provide a device.

According to a fourth aspect of the present invention, a reverse bias voltage is applied between the pn junction of the semiconductor device to change the width of the depletion layer of the semiconductor device, and the semiconductor device while changing the reverse bias voltage. The present invention provides a semiconductor evaluation apparatus capable of measuring a pn junction position and a minority carrier diffusion length of a semiconductor device with higher resolution by performing the evaluation of the semiconductor device, and more accurately evaluating the semiconductor device. It is intended to be.

According to a fifth aspect of the present invention, a minority carrier is locally excited in accordance with a change in the depth of penetration of near-field light into a semiconductor device by changing the wavelength of light introduced into the probe. By detecting a change in current and evaluating the semiconductor device, the pn junction positions at different depths and the diffusion length of minority carriers of the semiconductor device are measured with higher resolution, and the evaluation of the semiconductor device is performed. It is an object of the present invention to provide a semiconductor evaluation device that can perform the test more accurately.

[0022]

According to a first aspect of the present invention, there is provided a semiconductor evaluation apparatus for detecting a defect in a semiconductor device by utilizing near-field interaction and evaluating the semiconductor device. A mounting table on which the semiconductor device is mounted, and a tip which is disposed close to the semiconductor device mounted on the mounting table and whose tip is formed to have a size equal to or smaller than a predetermined light wavelength and A probe having a fine opening formed at a tip thereof, position control means for controlling a relative position between the probe and the semiconductor device, and light introducing means for introducing the light of the predetermined wavelength to the probe, While changing the relative position of the semiconductor device and the probe by position control means, introducing the light from the light introducing means to the probe, the semiconductor device and The near-field interaction between the serial probe locally excites the minority carriers in the semiconductor device, by detecting a change in the excitation current, by performing evaluation of the semiconductor devices, it has achieved the above objects.

According to the above construction, the tip is formed close to the semiconductor device mounted on the mounting table, the tip is formed to have a size equal to or smaller than the predetermined light wavelength, and a minute opening is formed at the tip. Since the minority carriers are excited in the semiconductor device by the near-field interaction between the semiconductor device and the probe while changing the relative position between the probe and the semiconductor device, the change in the photoexcitation current is detected, and the semiconductor device is evaluated. In addition, the pn junction position of the semiconductor device, the diffusion length of minority carriers, and the like can be measured with high resolution, and the semiconductor device can be evaluated more accurately.

[0024] In this case, for example, as set forth in claim 2, the semiconductor evaluation device comprises: a vibration means for vibrating the probe in a horizontal direction at a resonance frequency of the probe;
Vibration detecting means for detecting the vibration of the probe vibrated by the vibrating means, wherein the position control means interposes the probe and the semiconductor device based on a detection result of the vibration detecting means. The distance may be controlled to a distance equal to or less than the length of the small opening diameter of the probe.

According to the above configuration, the probe is vibrated in the horizontal direction at the resonance frequency of the probe, the vibration of the vibrating probe is detected, and the position between the probe and the semiconductor device is determined based on the detection result. Control.
The distance between the probe and the semiconductor device can be controlled more precisely, and the probe is vibrated only at the resonance frequency, so that the pn junction position of the semiconductor device and the diffusion length of minority carriers can be further improved with higher resolution. In addition, the measurement can be performed with a simple configuration, and the evaluation of the semiconductor device can be performed more accurately and inexpensively.

In addition, for example, the semiconductor evaluation device detects a change in the photoexcitation current and detects a change in a light emission phenomenon due to a near-field interaction between the semiconductor device and the probe. The semiconductor device may be evaluated by detecting with the probe.

According to the above configuration, the change in the photoexcitation current is detected, and the change in the light emission phenomenon due to the near-field interaction between the semiconductor device and the probe is detected by the probe to evaluate the semiconductor device. p-
The n-junction position, the diffusion length of minority carriers, and the like can be measured, and the defect position and defect distribution of the semiconductor device can be measured with high resolution, so that the semiconductor device can be evaluated more accurately.

Further, for example, as set forth in claim 4, the semiconductor evaluation device further includes voltage applying means for applying a predetermined bias voltage to the semiconductor device,
The pn of the semiconductor device is obtained by the voltage applying means.
A reverse bias voltage may be applied between the junctions to change the width of the depletion layer of the semiconductor device, and the semiconductor device may be evaluated while changing the reverse bias voltage.

According to the above structure, the p-
Since a reverse bias voltage is applied between the n junctions to change the width of the depletion layer of the semiconductor device and the semiconductor device is evaluated while changing the reverse bias voltage,
The pn junction position and the minority carrier diffusion length of the semiconductor device can be measured with higher resolution, and the evaluation of the semiconductor device can be performed more accurately.

Also, for example, as set forth in claim 5, the semiconductor evaluation apparatus changes the wavelength of the light introduced from the light introducing means to the probe, and transmits the near-field light to the semiconductor device. The penetration depth is changed, minority carriers are locally excited according to the change in the penetration depth of the near-field light into the semiconductor device, and the change in the excitation current is detected to evaluate the semiconductor device. It may be something.

According to the above configuration, the wavelength of light introduced into the probe is changed, and minority carriers are locally excited in accordance with the change in the depth of penetration of the near-field light into the semiconductor device,
Since the semiconductor device is evaluated by detecting the change in the excitation current, the pn junction position and the minority carrier diffusion length at different depths of the semiconductor device can be measured with higher resolution. The device can be evaluated more accurately.

[0032]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. It should be noted that the embodiments described below are preferred embodiments of the present invention, and therefore, various technically preferable limitations are added. However, the scope of the present invention is not limited to the following description. The embodiments are not limited to these embodiments unless otherwise specified.

FIG. 1 is a diagram showing one embodiment of a semiconductor evaluation device of the present invention. FIG. 1 is a schematic configuration diagram of a semiconductor evaluation device 1 to which one embodiment of the semiconductor evaluation device of the present invention is applied. It is.

In FIG. 1, the semiconductor evaluation device 1 has a PZ
T-stage 2, probe 3, vibration mechanism 4, feedback circuit 5, laser diode (LD) 6, photodiode (PD) 7, personal computer 8, semiconductor laser 9, chopper 10, reflector 11, lock-in amplifier 12 and a bias circuit 13, etc.
A semiconductor device to be evaluated, which is the sample 14, is placed on the ZT stage 2.

A bias voltage is applied from a bias circuit (voltage applying means) 13 to the sample 14 mounted on the PZT stage (mounting table) 2, and the position of the sample 14 and the probe 3 is controlled by a personal computer. 8 does. That is, the personal computer 8 operates in the X direction,
By moving the PZT stage 2 in the Y direction and the Z direction,
The position of the sample 14 and the probe 3 on the ZT stage 2 is controlled, and functions as position control means.

The probe 3 is irradiated with laser light from a laser diode 6, and the reflected light is received by a photodiode 7. The photodiode 7 outputs the detection result to the personal computer 8 via the feedback circuit 5. The personal computer 8 has P
By performing position control of the ZT stage 2 and detecting lock-in, a feedback signal in the height direction of the probe 3 is obtained, and position control of the probe 3 and the sample 14 is performed.

That is, the vibration mechanism (vibration means) 4 applies horizontal vibration to the probe 3, and for example, PZT or the like is used. The vibration mechanism 4 has a function of vibrating the probe 3 in the horizontal direction at the resonance frequency of the probe 3, and the resonance frequency of the probe 3 is approximately several kHz to 100 kHz. The vibrating mechanism 4 vibrates the probe 3 at the resonance frequency of the probe 3 so that the probe 3
When the sample and the sample 14 are brought close to each other, a shear force (shear force) in a lateral direction (horizontal direction) is generated between the probe 3 and the sample 14
Works, and the amplitude of the probe 3 decreases. The amplitude of the probe 3 is compared with the laser diode 6 and the photodiode 7.
And the height of the PZT stage 2 (Z direction) is adjusted by the personal computer 8 to accurately control the distance between the probe 3 and the sample 14.
The laser diode 6, the photodiode 7, and the feedback circuit 5 function as vibration detecting means.

Then, by plotting the information in the height direction two-dimensionally, information on the two-dimensional height distribution (Z-direction distribution) of the sample 14 can be obtained. Further, the probe 3 is irradiated with laser light from the laser diode 6,
By detecting the reflected diffracted light with the photodiode 7 and locking it in using the lock-in amplifier 12, a feedback signal in the height direction of the probe 3 can be obtained.

A laser beam emitted from a semiconductor laser 9 is incident on one end of the probe 3 via a chopper 10 and a reflecting mirror 11. An evanescent field is generated in the minute opening formed at the end (tip), and the sample 14 can be irradiated (see Applied Physics, Vol. 65, No. 1, (1996), page 2).

That is, the probe 3 is formed so that its tip is smaller than the wavelength of the incident light.
An evanescent field is generated from the minute opening at the tip because the tip has a small opening set to a radius of curvature that is sufficiently smaller than the wavelength of light at the tip and the laser beam is incident from the other end.

When such a probe 3 receives a laser beam from the end opposite to the tip, an evanescent field is generated in the minute opening at the tip, and the probe 14 can irradiate the sample 14. At the time of measurement, since the above-mentioned shear stress is monitored at the same time, the distribution of light corresponding to the shape of the sample 14 can be measured. In addition, by connecting a monochromator to this portion, it is possible to correspond to each wavelength. Sample 1
4 can be measured, that is, the distribution over the location of the defect or the like can be measured.

The shape and optical characteristics of the surface of the sample 14 can be measured by generating an evanescent field from the minute opening by bringing the tip of the probe 3 having the small opening formed close to the sample 14. The resolution in this case is determined by the small opening diameter of the tip of the probe 3 and the distance between the probe 3 and the sample 14, and is not affected by the diffraction limit of light as in a normal optical microscope.
Only the light emission from the 4 minute regions can be selectively extracted. Then, the probe 3 is attached to the minute light emitting portion of the sample 14.
Are brought close to each other, the short-range interaction (proximity interaction) between the probe 3 and the light-emitting portion of the sample 14 changes the intensity and lifetime of the light-emitting portion under the influence of the probe 3. This proximity interaction decreases in inverse proportion to the cube of the distance when the distance from the sample 14 increases, and is a component that exists only when the distance between the probe 3 and the surface of the sample 14 is close.
Then, the probe 3 needs a shielding structure so that components of light emitted from portions other than the light emitting portion to be measured do not enter the probe 3. That is, components of light emitted from portions other than the light-emitting portion become noise, so that the probe 3 needs a sufficient shielding structure to improve the S / N ratio of the signal component.

The probe 3 performing the above-described operation is formed by, for example, sharpening a quartz fiber by a chemical etching with a mixed solution of hydrofluoric acid and then coating it with a metal to form a fine opening at the tip, or by using silicon as an atom. It is formed by attaching a light receiving structure of a photodiode to a root portion of a cantilever for an atomic force microscope, or by forming a minute opening by anisotropic etching of silicon.

The probe 3 is coated with, for example, a metal film (for example, gold, silver, aluminum, nickel, or the like) having a thickness of about 100 to 200 nm in order to sufficiently obtain the shielding structure. The minute opening at the tip of the probe 3 is formed by depositing a metal or coating an organic thin film while rotating the probe 3 obliquely.
It can be formed by wet etching with an appropriate etching solution.

As described above, the tip of the probe 3 is coated with a metal film for blocking the propagating light component, and has a fine aperture of several tens of nm. Only the field light component can be detected.

When the sample 14 is irradiated with near-field light from the probe 3, particularly when the sample 14 is irradiated with near-field light near the pn junction of the sample 14, electrons in the valence band of Si are emitted. An electron-hole pair is generated over the band gap. The semiconductor evaluation device 1 detects a change in the photoexcitation current that flows when the electron-hole pairs diffuse in the sample 14 and evaluates the sample 14, that is, the semiconductor device, with the personal computer 8.

That is, in the semiconductor evaluation device 1, the personal computer 8 controls the chopper 10 based on the lock-in of the lock-in amplifier 12 so that the laser light emitted from the semiconductor laser 9 is resonated with the vibration of the probe 3. The modulated laser light is introduced into the probe 3 via the reflecting mirror 11. The semiconductor evaluation apparatus 1 generates an evanescent field in the probe 3 by the modulated laser light, and vibrates the probe 3 by the vibration mechanism 4. In this state, the personal computer 8 operates the PZT stage 2 based on the lock-in amplifier 12 and the lock-in feedback signal of the feedback circuit 5 as described above.
Is performed to control the position of the sample 14 and the probe 3, and based on the detection result of the feedback circuit 5, the photoexcitation current flowing through the sample 14 is measured to evaluate the sample 14, ie, the semiconductor device. I do.

The semiconductor evaluation apparatus 1 captures light generated from the sample 14 by the probe 3 and detects the light with a monochromator (not shown). From the detection result, the light emission distribution, that is, the location and distribution of defects and the like are determined. Measure.

Next, the operation of the present embodiment will be described. In the semiconductor evaluation apparatus 1, a sample 14 which is a semiconductor device is mounted on a PZT stage 2.
A bias voltage is applied via the in-amplifier 12. The semiconductor evaluation device 1 includes a personal computer 8
The position of the PZT stage 2 is adjusted in the three directions of XYZ, and the coarse position adjustment of the sample 14 and the probe 3 on the PZT stage 2 is performed in advance. The probe 3 is vibrated at a resonance frequency of 3, and the amplitude of the probe 3 at that time is detected by receiving the laser beam irradiated from the laser diode 6 to the probe 3 by the photodiode 7. The vibration applied to the probe 3 by the vibration mechanism 4 is the vibration at the resonance frequency of the probe 3 as described above.

The personal computer 8 moves the sample 14 in the direction of the probe 3 via the PZT stage 2 so that the sample 14 approaches the probe 3. That is, while the probe 3 is given vibration at the resonance frequency,
, A lateral shear stress acts between the probe 3 and the sample 14, and the amplitude of the probe 3 decreases.
The amplitude of the probe 3 is detected by detecting the reflected and diffracted light of the laser light emitted from the laser diode 6 to the probe 3 by the photodiode 7, and the lock-in detection signal from the feedback circuit 5 detects the amplitude of the probe 3 in the height direction. (Z direction) feedback signal,
The position of the sample 14 is controlled.

In this state, the personal computer 8
Controls the chopper 10 to emit laser light from the semiconductor laser 9 and modulates the laser light emitted from the semiconductor laser 9 in synchronization with the oscillation at the resonance frequency. Make it incident.

When the laser beam is incident on the probe 3, the near-field light leaks from the minute opening at the tip of the probe 3 and irradiates the sample 14. When the sample 14 is irradiated with near-field light, electrons in the valence band of Si jump over the band gap to generate electron-hole pairs, and the electron-hole pairs diffuse through the semiconductor sample 14, It is detected as a photoexcitation current.

For example, electrons (minority carriers) generated in the p region are combined with majority carriers and die before reaching the vacant layer, but a small number of electrons arriving in the vacant layer and the n region are vacant. Since the recombination probability is small in the dead layer and the n region,
The current is detected as it is. In particular, since the recombination of carriers is small in the void layer, all the electrons that have reached the void layer are detected as current. Therefore, the portion where the current intensity is the highest coincides with the joining position.

Further, the semiconductor evaluation apparatus 1 evaluates the sample 14 by applying a reverse bias voltage to the sample 14. That is, when a reverse bias is applied to the pn junction of the sample 14, the vacant layer expands, and the signal half-width of the near-field excitation current obtained increases. At this time, if the half-value width of the signal value of the near-field excitation current is ΔW (E), the concentration of the doped impurity is Nd, and the width of the depletion layer is D (E), the following equation is established.

D (E) −D (0) = (1 / Nd) ^1/2 · C · (ΔW (E) −ΔW (0)) (1) where C is a proportional constant , E are bias voltages.

By calculating the slope of the above equation (1),
The impurity concentration of the sample 14 can be measured.

Further, the semiconductor evaluation device 1 evaluates the sample 14 by changing the excitation wavelength, that is, by changing the wavelength of the laser light of the semiconductor laser 9 to be incident on the probe 3. That is, when the excitation wavelength is changed, the penetration depth of the near-field light coupled to the sample 14 from the small aperture of the probe 3 into the sample 14 changes. As the excitation wavelength becomes shorter, the penetration depth becomes smaller. Become smaller. For example,
For a Si substrate, the light of 515 nm of an argon laser has a wavelength of 685 nm and the light of 415 nm has a wavelength of 280 nm.
For light of m and 351 nm, it changes to about 10 nm. Therefore, by changing the wavelength of the laser light to be introduced into the probe 3, which is the excitation light, information of different depths of the sample 14 can be obtained.

The semiconductor evaluation apparatus 1 evaluates the sample 14 by detecting light generated from the sample 14 when the probe 3 irradiates an evanescent field. That is, the semiconductor evaluation device 1 captures the light generated from the sample 14 when the evanescent field is irradiated from the probe 3 with the probe 3 and detects the light with the monochromator (not shown).
From this detection result, the emission distribution corresponding to each wavelength, that is, the location and distribution of the defect or the like of the sample 14 are measured.

As described above, the semiconductor evaluation apparatus 1 according to the present embodiment is disposed close to the sample 14 which is a semiconductor device mounted on the PZT stage 2 which is a mounting table, and has a tip having a predetermined light wavelength. The probe 3 and the sample 14 each having the following size and having a small opening at the end thereof.
The minority carrier is excited in the sample 14 by the near-field interaction between the sample 14 and the probe 3 while changing the relative position of the sample 14 and the change in the photoexcitation current is detected to evaluate the sample 14.

Therefore, the pn junction position and the minority carrier diffusion length of the sample 14 can be measured with high resolution, and the semiconductor device as the sample 14 can be evaluated more accurately.

Further, the semiconductor evaluation apparatus 1 vibrates the probe 3 in the horizontal direction at the resonance frequency of the probe, detects the vibration of the probe 3 that is vibrated, and based on the detection result, the probe 3 and the sample 14. During the position control.

Therefore, the distance between the probe 3 and the sample 14 can be controlled more precisely, and the probe 3 is vibrated only at the resonance frequency, so that the pn
The junction position, the diffusion length of minority carriers, and the like can be measured with higher resolution and a simple configuration, and the evaluation of the sample 14 as a semiconductor device can be performed more accurately and at lower cost. .

Further, the semiconductor evaluation apparatus 1 evaluates the sample 14 by detecting a change in the photoexcitation current and detecting a change in the light emission phenomenon due to the near-field interaction between the sample 14 and the probe 3 with the probe 3. I have.

Therefore, the pn junction position and minority carrier diffusion length of the sample 14 can be measured, and the defect position and defect distribution of the sample 14 can be measured with high resolution. The evaluation of the sample 14 can be performed more accurately.

Further, the semiconductor evaluation device 1
A reverse bias voltage is applied between the -n junctions to change the width of the depletion layer of the sample 14, and the sample 14 is evaluated while changing the reverse bias voltage.

Therefore, the pn junction position and the minority carrier diffusion length of the sample 14 can be measured with higher resolution, and the sample 14 as a semiconductor device can be evaluated more accurately.

Further, the semiconductor evaluation device 1
The minority carriers are locally excited according to the change in the depth of penetration of the near-field light into the sample 14 by changing the wavelength of the light to be introduced into the sample 14, and the change in the excitation current is detected to evaluate the sample 14. Is going.

Therefore, p of different depths of sample 14
The -n junction position, the diffusion length of minority carriers, and the like can be measured with higher resolution, and the evaluation of the sample 14 as a semiconductor device can be performed more accurately.

Although the invention made by the inventor has been specifically described based on the preferred embodiments, the invention is not limited to the above-described embodiment, and various modifications may be made without departing from the gist of the invention. It goes without saying that it is possible.

[0070]

According to the semiconductor evaluation apparatus of the first aspect of the present invention, the tip is formed close to the semiconductor device mounted on the mounting table and the tip is formed to have a size equal to or smaller than a predetermined light wavelength. At the same time, while changing the relative position between the probe and the semiconductor device having a micro opening formed at the tip, the near-field interaction between the semiconductor device and the probe excites minority carriers in the semiconductor device and detects the change in the photoexcitation current. Since the semiconductor device is evaluated, the pn junction position of the semiconductor device, the diffusion length of minority carriers, and the like can be measured with high resolution, and the semiconductor device can be evaluated more accurately.

According to the semiconductor evaluation device of the present invention, the probe is vibrated in the horizontal direction at the resonance frequency of the probe, the vibration of the vibrating probe is detected, and the probe is detected based on the detection result. And the position of the semiconductor device is controlled, so that the distance between the probe and the semiconductor device can be controlled more precisely, and by vibrating only at the resonance frequency of the probe, the pn junction position of the semiconductor device and The diffusion length of minority carriers and the like can be measured with higher resolution and a simpler configuration, and semiconductor devices can be evaluated more accurately and at lower cost.

According to the semiconductor evaluation device of the third aspect of the present invention, the change in the photoexcitation current is detected, and the change in the light emission phenomenon due to the near-field interaction between the semiconductor device and the probe is detected by the probe. Since the evaluation is performed, the pn junction position and the diffusion length of minority carriers of the semiconductor device can be measured, and the defect position and defect distribution of the semiconductor device can be measured with high resolution. Can be performed more accurately.

According to the semiconductor evaluation device of the present invention, a reverse bias voltage is applied between the pn junctions of the semiconductor device to change the width of the depletion layer of the semiconductor device, and the reverse bias voltage is changed. Since the evaluation of the semiconductor device is performed while changing the value, the pn junction position and the diffusion length of minority carriers of the semiconductor device can be measured with higher resolution, and the evaluation of the semiconductor device can be performed more accurately. Can be.

According to the semiconductor evaluation apparatus of the present invention, the minority carriers are locally changed according to the change in the penetration depth of the near-field light into the semiconductor device by changing the wavelength of the light introduced into the probe. And the semiconductor device is evaluated by detecting the change in the excitation current, so that the pn junction positions at different depths and the diffusion length of minority carriers of the semiconductor device can be measured with higher resolution. And the semiconductor device can be evaluated more accurately.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a semiconductor evaluation device to which an embodiment of a semiconductor evaluation device of the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor evaluation apparatus 2 PZT stage 3 Probe 4 Vibration mechanism 5 Feedback circuit 6 Laser diode 7 Photodiode 8 Personal computer 9 Semiconductor laser 10 Chopper 11 Reflecting mirror 12 Lock-in amplifier 13 Bias circuit 14 Sample

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Claims (5)

[Claims] 1. A semiconductor evaluation apparatus for detecting a defect of a semiconductor device by utilizing near-field interaction to evaluate the semiconductor device, comprising: a mounting table on which the semiconductor device is mounted; A probe which is disposed close to the semiconductor device mounted on the mounting table and whose tip is formed to have a size equal to or smaller than a predetermined light wavelength and has a fine opening at the tip, A position control unit that controls a relative position with respect to the semiconductor device; and a light introducing unit that introduces the light of the predetermined wavelength into the probe. The position control unit changes a relative position between the semiconductor device and the probe. While introducing the light from the light introducing means to the probe, and causing the semiconductor device and the probe to perform near-field interaction. Locally it excites the minority carriers, by detecting a change in the excitation current, the semiconductor evaluation device, characterized in that the evaluation of the semiconductor device. 2. The semiconductor evaluation device according to claim 1, wherein said semiconductor evaluation device includes: a vibration means for vibrating said probe in a horizontal direction at a resonance frequency of said probe; a vibration detection means for detecting vibration of said probe vibrated by said vibration means; And the position control means controls the distance between the probe and the semiconductor device to a distance equal to or less than the length of the small opening diameter of the probe based on the detection result of the vibration detection means. The semiconductor evaluation device according to claim 1, wherein: 3. The semiconductor evaluation device detects a change in the photoexcitation current and detects a change in a light emission phenomenon due to a near-field interaction between the semiconductor device and the probe with the probe. 3. The semiconductor evaluation device according to claim 1, wherein the evaluation is performed. 4. The semiconductor evaluation device further includes voltage applying means for applying a predetermined bias voltage to the semiconductor device, and the voltage applying means applies a reverse bias voltage between pn junctions of the semiconductor device. 4. The semiconductor according to claim 1, wherein the semiconductor device is evaluated while changing a width of a depletion layer of the semiconductor device and changing the reverse bias voltage. Evaluation device. 5. The semiconductor evaluation device changes a wavelength of the light introduced from the light introducing means to the probe,
The depth of penetration of near-field light into the semiconductor device is changed, minority carriers are locally excited according to the change in depth of penetration of the near-field light into the semiconductor device, and the change in the excitation current is detected. The semiconductor evaluation device according to claim 1, wherein the semiconductor device is evaluated by performing the evaluation.