JP3220500B2 - Soft X-ray detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soft X-ray detector used as an imaging device in an X-ray telescope, a soft X-ray microscope, a soft X-ray inspection device, and the like.

[0002]

2. Description of the Related Art It is known that a soft X-ray detector includes an MCP (micro channel plate), a scintillation counter, an imaging plate, a semiconductor detector, a soft X-ray solid-state imaging device such as a CCD, and the like.

[0003] Among them, the MCP, the scintillation counter and the imaging plate lack the ease of handling, and when these are used, there is a disadvantage that the structure of the apparatus becomes large and complicated. Furthermore, MCP
Is excellent in detection wavelength characteristics and low in sensitivity to light outside the soft X-ray region, but is expensive and has the drawback that the spatial resolution is restricted by the thickness of the microchannels constituting the MCP (at least about 12 μm). There is. Further, although the imaging plate is excellent in spatial resolution, it has a drawback that it lacks real-time signal detection. In contrast to these, the solid-state imaging device for soft X-rays has the advantages that it can detect signals in real time, and is inexpensive and easy to handle. Therefore, if this is used, it is possible to provide a soft X-ray detection device having a small size and a simple structure.

[0004]

However, the solid-state imaging device for soft X-rays has a lower sensitivity to soft X-rays than the above-described MCP and the like, and has a lower sensitivity to light other than the soft X-ray region such as visible light. However, there is a problem that it is difficult to detect soft X-rays using the solid-state imaging device alone because of its high sensitivity.

FIG. 9 shows a conventional CC used for soft X-ray detection.
The structure of a D-type solid-state image sensor is shown, where K is p
A photodiode formed by providing an n ⁻ -type region N on the surface of a mold substrate L; T, a transfer gate provided in a region adjacent to the diode K; S, an aluminum light shield provided in a region above the transfer gate T; Q is incident light. The incident light Q incident on the solid-state imaging device reaches the photodiode K, where it is photoelectrically converted, and the photoelectrically converted electric signal is transferred through the transfer gate T. The aluminum light shield S prevents noise from entering the transfer gate T. As described above, since the conventional solid-state imaging device is provided with the aluminum light shield S, the structure of the surface of the imaging device is complicated. In order to protect these structures, as shown in FIG. A protective film M was required. Since the protective film M absorbs most of the incident soft X-rays, the amount of the soft X-rays reaching the photodiode K is small in this state. Therefore, when detecting soft X-rays, a fluorescent film such as Gd ₂ O ₂ S: Tb is applied to the surface of the CCD, and the soft X-rays are converted into visible light by the fluorescent film and then photoelectrically converted. (For example, Springer-Verlag X-ray Microscopy II,
p.127, 1987). However, the quantum efficiency is smaller than 1, the conversion efficiency is poor, and the sensitivity is low.

In an apparatus for detecting soft X-rays using such a solid-state image pickup device, a continuous-wavelength light source such as a laser plasma light source or a radiant light (SR) used as a light source is located outside the soft X-ray region. Since light having a wavelength is also emitted, visible light or the like overlaps with the soft X-rays and enters the solid-state imaging device, which becomes noise with respect to the soft X-rays. Therefore, when a high-resolution observation image is to be obtained by detecting only soft X-rays having a short wavelength, for example, as in a soft X-ray microscope, the light is incident on a solid-state imaging device in order to prevent polymerization of the image due to visible light. Light other than soft X-rays needs to be removed by a spectroscope or the like. However, in this case, the apparatus becomes large and complicated, and the advantage of using the solid-state imaging device as the soft X-ray detector is lost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide high sensitivity to soft X-rays and low cost. To provide a soft X-ray detector that is easy to use.
Another object of the present invention is to provide a soft X-ray detector which has low sensitivity to light outside the soft X-ray region such as visible light and can selectively detect only soft X-rays. .

[0008]

In the soft X-ray detector according to the present invention, a surface electrode layer and a soft X-ray having a thickness sufficient to allow soft X-rays to pass therethrough are provided on the incident side of the semiconductor detector. By adopting a laminated structure to provide a photoelectric conversion layer to be converted, by detecting the charge generated in the photoelectric conversion layer with a semiconductor detector,
Soft X-rays are detected. Specifically, the thickness of each layer is set so as to satisfy the following conditions. Condition _{(A) d A ≧ 0.183λ /} K A condition _{(B) d B ≦ 0.183λ /} K B where, d _A is the thickness of the photoelectric conversion layer, d _B is the thickness of the surface electrode layer, K _A is the absorption coefficient for light having a wavelength λ of a substance absorption coefficient for light having a wavelength λ of the material constituting the photoelectric conversion layer, K _B is constituting the surface electrode layer.

If the above conditions are satisfied, at least 10% of soft X-rays pass through the surface electrode layer, and 90% or more of them are absorbed by the photoelectric conversion layer. Therefore, if the charge generated by the soft X-rays absorbed by the photoelectric conversion layer is detected by the semiconductor detector, a soft X-ray detector having good sensitivity to the soft X-rays can be obtained. Further, in addition to these configurations, a filter for removing unnecessary light such as visible light may be provided on the incident side of the surface electrode layer, or its material and thickness may be appropriately adjusted so that the surface electrode layer itself removes visible light. In this case, a soft X-ray detector that can effectively detect only soft X-rays can be obtained.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on embodiments. FIG. 1 shows a cross section of one pixel of an X-ray image sensor using an AMI (internal amplification type solid-state imaging device).
In the figure, on the surface of a p-type substrate A, a diode D provided with an n ⁺ -type region B and a field oxide film C covering the surface of the substrate A are formed. The contact portion D ′ of the diode D is coupled to the photoelectric conversion layer 1 via a first aluminum layer E, a second aluminum layer F, and a third aluminum layer G. In the figure, H, I and J are a first aluminum layer E, a second aluminum layer F and a third aluminum layer G.
An insulating film made of SiO ₂ or the like for electrically insulating between the two, a surface electrode layer provided on the surface of the photoelectric conversion layer 1,
Is a pixel electrode, and 4 is a soft X-ray. Between the photoelectric conversion layer 1 and the surface electrode layer 2 and between the photoelectric conversion layer 1 and the pixel electrode 3,
In many cases, a Si ₃ N ₄ layer having a rectifying action of about 100 ° is provided. As described above, since the photoelectric conversion layer 1 that performs photoelectric conversion is only covered by the thin surface electrode layer 2, the soft X-rays 4 that enter the sensor reach the photoelectric conversion layer 1 without being attenuated. Therefore, the sensitivity of soft X-rays can be increased.

As a material constituting the photoelectric conversion layer 1, a semiconductor such as Si or GaAsP is used, and these materials have high sensitivity to soft X-rays, that is, a high quantum efficiency.
For example, as shown in FIG.
The quantum efficiency of Au Schottky diodes for soft X-rays is close to 100 (Proc. SPIE 733, p. 481, 1986). That is, the sensitivity as the soft X-ray detector can be further increased by forming the photoelectric conversion layer 1 in a laminated structure and employing a substance having high sensitivity.

FIG. 3 shows the band gaps of various substances. As is clear from FIG. 3, since the energy of light in the soft X-ray region is 20 eV or more, valence electrons of all semiconductors and insulators can be excited by the conductor.
Therefore, all semiconductors and insulators can be used for the photoelectric conversion layer 1, but semiconductors are more preferable in terms of mobility of electrons and holes. Figure 4 shows the bandgap of main semiconductors at room temperature (Applied Electronic Properties, Corona,
1989).

Next, the conditions for selecting the thickness of each layer for removing unnecessary light outside the soft X-ray region while maintaining the sensitivity to soft X-rays will be described by taking visible light removal as an example. As described above, when a semiconductor is used for the photoelectric conversion layer 1, the photoelectric conversion layer 1 has sensitivity to light in a wide wavelength range from visible light to soft X-rays. Therefore, when selecting a substance to be used for the surface electrode layer 2, if a substance having a property of reflecting or absorbing visible light and transmitting soft X-rays is adopted, the visible light can be effectively removed.

The material of the surface electrode layer 2 is InSnO
A nitride or metal such as SiO ₂ or SiO ₂ is preferable, but the thickness of the surface electrode layer 2 needs to be appropriately selected in order to reflect or absorb visible light and transmit soft X-rays. That is,
Assuming that the absorption coefficient of the complex refractive index at the wavelength λ is K, the intensity transmittance T of the light of the material having the thickness d with respect to the light of the wavelength λ is expressed by T = exp {−4πKd / λ} (1) Is done.

The magnitude of the conversion efficiency in the photoelectric conversion layer 1 is proportional to the magnitude of the soft X-ray absorptivity in the photoelectric conversion layer 1. In other words, the conversion efficiency increases as the amount of the soft X-rays transmitted through the photoelectric conversion layer 1 decreases. Photoelectric conversion layer 1
Is the thickness of d _A , and the absorption coefficient for soft X-rays of wavelength λ _X is K
_A, when the transmittance of the soft X-ray and T _X, is expressed as _{T X = exp {-4πK A d} A / λ X} ··· (2). Thus, conditions for the thickness d _A for the following transmission T _X is a _{d A ≧ -lnT X · λ X} / (4πK A) ··· (3). Note that ln is a natural logarithm. For example, the condition of the thickness d _A when absorbing 90% or more of soft X-rays incident on the photoelectric conversion layer 1 is determined by the transmittance T in the above equation (3).
Substituting T _X = 0.1 in _X, the _{d A ≧ 0.183λ X / K A} ··· (4).

On the other hand, in the surface electrode layer 2, it is necessary to minimize the amount of soft X-rays absorbed. Although depending on the level of the conversion efficiency of the photoelectric conversion layer 1, the surface electrode layer 2 has the highest soft X-ray absorption of 90%,
When allowed to ensure 10% of the transmittance at least in other words, the thickness condition of d _B of the surface electrode layer 2, the wavelength λ
Table absorption coefficient of the surface electrode layer 2 for soft X-ray of the _X When K _B, becomes opposite conditions for the above formula (4), and _{d B ≦ 0.183λ X / K B} ··· (5) Is done.

In order to efficiently remove visible light from the surface electrode layer 2, it is necessary to appropriately select the thickness of the surface electrode layer 2. When the absorption coefficient of the surface electrode layer 2 for visible light of wavelength λ _V is K _V , and the absorption coefficient of the surface electrode layer 2 for soft X-rays of wavelength λ _X is K _X , the surface electrode layer 2 absorbs soft X-rays. the thickness condition d _B of the material for more than N times greater than the transmittance transmittance of visible light, the equation from (1), N · exp { -4πK V d B / λ V} ≦ exp {-4πK _X d _B / _{λ X}} given with (6). By deploying the thickness d _B of _{this, d B ≧ -lnN / {-} 4π (K V / λ V -K X / λ X)} ··· (7) becomes, which is for the unnecessary light removing thick It is a condition of d _B. For example, in the case of N = 100, in the case of _{d B ≧ 0.366 / (K V} / λ V -K X / λ X) ··· (8) N = 1000, d B ≧ 0.55 / ( K _V / λ _V −K _X / λ _X ) (9)

In practice, in order to detect soft X-rays effectively, the transmittance of the surface electrode layer 2 for the soft X-rays is set to 0.1.
One or more is required. Further, in order to effectively remove visible light, it is desirable that the transmittance of visible light be 1/100 or less of the transmittance of soft X-rays.

The above conditions are the same when a filter is provided on the surface electrode layer 2 and visible light is removed by the action of the filter. That is, the surface electrode layer 2
When a filter is provided above the filter, if the filter is required to have a transmittance of at least 10%,
The condition of the thickness d _c of the filter is represented by d _c ≦ 0.183λ _X / K _XF (10) where K _XF is the absorption coefficient of the filter for soft X-rays of wavelength λ _X. When the absorption coefficient of the filter for visible light of wavelength λ _V is K _VF , the soft X
For transmittance with respect to a line at least N times larger than the transmittance for visible light, the conditions of the thickness d _c of the filter, from the formula (1), N · exp { -4πK VF d c / λ V} ≦ exp It is given a _{{-4πK XF d c / λ X} } ··· (11). If this is developed for the thickness d _c , then d _c ≧ −lnN / {− 4π (K _VF / λ _V −K _XF / λ _X )} (12), which is a filter for removing unnecessary light Thickness d
It becomes the condition of _c . For example, when N = 100, d _c ≧ 0.366 / (K _VF / λ _V −K _XF / λ _X ) (13) When N = 1000, d _c ≧ 0.55 / ( _{K VF / λ V -K XF /} λ X) becomes (14).

Also, Be, Al, Sc, Ti, V, Cr,
Mn, Fe, Co, Ni, Cu, Zn, Mo, Ag, I
Metals such as n, W, Pt, and Au cause metal reflection with respect to visible light.
When the thickness is 1 μm or more, almost no visible light is transmitted.
It is suitable as a material for the surface electrode layer 2 and the filter. In particular, Al, Cu, Ag, and Au have low electric resistance and are optimal as electrodes. However, these metals have soft X-rays because the absorption edge of each element exists in the soft X-ray region.
When importance is placed on the conversion efficiency of the line, it is preferable to select a substance that absorbs less soft X-rays at the wavelength used.

Next, a procedure for reading out the photoelectrically converted detection charge in the image pickup device having the above structure will be described.
FIG. 5 is an equivalent circuit of the image pickup device including the cross-sectional view of FIG. 1 shown in the frame of the dashed line, and in the figure, the frame of the broken line indicates one pixel. The AMI is an XY address type element that amplifies the optical information signal obtained by the photoelectric conversion unit in the same pixel and reads out the signal through the vertical and horizontal scanning switch circuits.

One pixel of the AMI is composed of an n ⁺ p photodiode D and three n-channel MOSFETs for reset (Trs), amplification (Ta) and vertical selection (Ty). The operating principle is that the photodiode D is reverse-biased and discharged by the photoelectric charges generated by the X-rays in the photoelectric conversion layer 1, and the potential is amplified by current and taken out. First, in the reset period, the photodiode D receives the initial potential Vrs via the reset transistor Trs.
(Positive potential). During the accumulation period, the electrons excited by the X-ray irradiation become the capacitance C of the photodiode D.
It is stored in the PD, and thus the potential of the photodiode D decreases according to the incident X-ray dose. This potential is applied to the gate of the amplification transistor Ta, and the current amplified according to the potential of the photodiode D is read. The holes generated by the X-ray irradiation flow to the surface electrode layer 2. The above is the operation within one pixel. When this element is used as an area sensor, first, the transistor Ty is turned on for one horizontal scanning period by the vertical scanning circuit, and during that time, the transistor Tx is turned on by the horizontal scanning circuit. Are sequentially turned on to read out one horizontal scanning line, and when one horizontal scanning line is completed, the same operation is repeated for the next horizontal scanning line to obtain a two-dimensional image signal.

As described above, the conversion signal is amplified after being amplified inside the element, so that the conversion efficiency is high. According to this configuration, the thin surface electrode layer 2 is formed on the photoelectric conversion layer 1. Since it is only present, the incident soft X-ray reaches the photoelectric conversion layer 1 without being attenuated, and the sensitivity is good. Therefore, S
/ N, and an output signal 10 to 100 times higher than that of a normal CCD can be obtained. S / N can be further increased by cooling. Also, there is an advantage that handling is easy without requiring a high vacuum environment unlike the MCP.

Hereinafter, specific structural examples of the surface electrode layer and the photoelectric conversion layer will be described. In the tables in each configuration example, the transmittance is shown as “1” when the light is completely transmitted. Structural Example 1 In this structural example, Al was used as a material constituting a surface electrode layer, and Si was used as a material constituting a photoelectric conversion layer. Al
Has an absorption coefficient of 6.28 for visible light (for example, a wavelength of 0.5166 μm) (Handbook of Optical Consta
nts of Solids, Academic Press). The absorption coefficient of Al for soft X-rays (for example, wavelength 39.8 °) is 0.0
2. The absorption coefficient of silicon is 0.02 (Henke Tabl
e (BL Hanke: Atomic Data & Nuclear Data Tables
Vol.27 No.1 pp. 1 to 144 (1982))). Therefore, when the transmittance of the surface electrode layer is calculated using the above equation (1), the values shown in Table 1 are obtained.

[0025]

[Table 1]

From the above equation (7), N = 1000 and N =
In the case of 100, the values are as shown in Table 2.

[Table 2]

The Al surface electrode layer and the Si photoelectric conversion layer having such thicknesses were formed as an AMI having a stacked photodiode structure shown in FIG. In this case, the thickness of the Si photoelectric conversion layer is 0.36 μm or more according to the above equation (4).

Configuration Example 2 In this configuration example, an AMI having a stacked photodiode structure was formed using Cu as a material for forming a surface electrode layer and Si as a material for forming a photoelectric conversion layer. The absorption coefficient of Cu for visible light (wavelength 0.5166 μm) is 2.6.
0, and the absorption coefficient for soft X-rays (wavelength: 39.8 °) is 0.004. When the transmittance of the surface electrode layer is calculated using the above equation (1), the values shown in Table 3 are obtained.

[0029]

[Table 3]

From equation (7), N = 1000 and N =
In the case of 100, the values are as shown in Table 4.

[Table 4]

Structural Example 3 In this structural example, an AMI having a stacked photodiode structure was formed using Ag as a material for forming a surface electrode layer and Si as a material for forming a photoelectric conversion layer. Ag has an absorption coefficient of 3.0 with respect to visible light (wavelength: 0.5166 μm).
7, and the absorption coefficient for soft X-rays (wavelength 39.8 °) is 0.004. When the transmittance of the surface electrode layer is calculated using the above equation (1), the values shown in Table 5 are obtained.

[0032]

[Table 5]

From equation (7), N = 1000 and N =
In the case of 100, the values are as shown in Table 6.

[Table 6]

Structural Example 4 This structural example uses 0.05% of each material of Be, Sc and Ti.
A thin film having a thickness of about 0.2 μm was formed and used as an AMI filter having a stacked photodiode structure. Be, Sc and Ti are suitable as filters because they have a small absorption coefficient in the soft X-ray region (absorption coefficient of 0.001 or less at a wavelength of 39.8 °) and cause metal reflection in visible light.

Table 7 shows the absorption coefficient and transmittance of each filter for soft X-rays having a wavelength of 39.8 °.

[Table 7] In Table 7, the upper part of the soft X-ray transmittance shows the case where the thickness of the filter is 0.05 μm, and the lower part shows the case where the thickness of the filter is 0.2 μm.

As can be seen from Table 7, the filters formed from these substances have a soft X-ray transmittance of 50% or more even at a thickness of 0.2 μm, and the reflectance of visible light is almost zero. Therefore, it is suitable as a filter.

Structural Example 5 This structural example has an Al surface electrode layer having a thickness of 300 ° and a thickness of 2 μm.
An AMI having a stacked-type photodiode structure having a Si photoelectric conversion layer having a thickness of 2 mm was formed, and a material such as B or C was further stacked on the Al surface electrode layer to form a filter. FIGS. 6A and 6B show the respective spectral transmittances when the B filter is 1500 ° and the C filter is 1000 ° (Opt.
Eng. 29 6 614, 1990). A thin film may be formed from an organic substance such as mylar and used as a filter.

Configuration Example 6 This configuration example is composed of Be, Al, Sc, Ti, V, Cr, M
n, Fe, Co, Ni, Cu, Zn, Mo, Ag, W,
A thin film having a thickness of about 0.05 to 0.2 μm was formed from each of Pt and Au substances, and this was used as an AMI filter having a stacked photodiode structure. Each of these substances has a peak of the absorption coefficient in the soft X-ray region,
The absorption coefficient changes as shown in FIG. Accordingly, in the wavelength region B where the absorption coefficient is small, which is located on the longer wavelength side than the peak A in FIG. In addition, these substances can serve as good filters in the above wavelength region B, since all of them show high reflectance due to metal reflection with respect to visible light.

Table 8 shows that Cu, Au, Mo, Ni, Pt, A
Specific numerical values of the absorption coefficient and the transmittance for g and W are shown.

[Table 8] In Table 8, the upper part of the soft X-ray transmittance shows the case where the thickness of the filter is 0.05 μm, and the lower part shows the case where the thickness of the filter is 0.1 μm.

The wavelength at which the filter efficiency is high for each substance is shown below. Wavelengths longer than Be 111 Ni 14Å longer wavelengths Al 170Å longer wavelengths Cu 13Å longer wavelengths Sc 30Å longer wavelengths Zn 12Å longer wavelengths Ti 27Å longer wavelengths Mo 54Å longer wavelengths V 24Å longer wavelengths Ag 34 波長 longer wavelengths Wavelengths longer than Cr 21 ° W 51 ° longer wavelengths Mn 19 ° longer wavelengths Pt 40 ° longer wavelengths Fe 18 longer wavelengths Au 37 ° longer wavelengths Co 16 ° longer wavelengths Be, Sc, and Ti are also shown in Configuration Example 4. But wavelength 3
It has good filter characteristics not only in the wavelength range of 9.8 ° but also in the wavelength range of this configuration example.

Configuration Example 7 This configuration example is used as a soft X-ray detector for a soft X-ray microscope.
I. FIG. 8 shows an imaging type soft X-ray microscope using a laser plasma light source.
Reference numerals 1 and 12 denote vacuum chambers for preventing soft X-rays from being absorbed by the atmosphere. The vacuum chambers have thin windows 13 and 14 in adjacent walls for transmitting soft X-rays. Reference numeral 15 denotes a laser plasma light source disposed in the vacuum chamber 11, and reference numeral 16 denotes a condenser lens using total reflection disposed in the vacuum chamber 11, and has a spheroidal structure.
Reference numeral 17 denotes a sample stage placed between the windows 13 and 14 in the atmosphere. Reference numeral 18 denotes a Schwarzschild type reflection objective lens using a multilayer film disposed in the vacuum chamber 12.
This multilayer film is obtained by alternately stacking Ni and Ti, and is used in a “water window” (wavelength: 23 to 44 °) region. Reference numeral 19 denotes an AMI having a stacked photodiode structure disposed in the vacuum chamber 12 and having a thickness of 2 mm on the surface of the AMI.
An Al surface electrode layer of 00 ° is formed. AMI19
May be laminated on the Al surface electrode layer in order to improve the spectral sensitivity characteristics.

The laser plasma light source 15 is a light source having a continuous wavelength and includes not only soft X-rays but also visible light. The condenser lens 16 is made of metal, and the Schwarzschild type reflection objective lens 18 also has a multilayer film made of metal. Therefore, the visible light is reflected by these metal reflections, and the visible light image of the sample is mixed with the soft X-rays in the AMI 19. Incident on. However, the visible light image can be effectively removed by the Al surface electrode layer of the AMI19, and the soft X-ray is reliably detected and photoelectrically converted by the photoelectric conversion layer of the AMI19. Can be. The same effect can be achieved when using radiation light including visible light instead of the laser plasma light source 15.

[0043]

As described above, the soft X-ray detector according to the present invention has high sensitivity to soft X-rays and low sensitivity to light outside the soft X-ray region such as visible light. Even if visible light is incident together with soft X-rays, soft X-rays can be reliably detected. Further, since the handling is easy and inexpensive, it is effective for reducing the size of the structure of the soft X-ray detecting device and reducing the device cost.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a soft X-ray detector according to the present invention.

FIG. 2 is a diagram showing quantum efficiency of a semiconductor.

FIG. 3 is a diagram showing electric characteristics and band gaps of a metal, a semiconductor, and an insulator.

FIG. 4 is a diagram showing a band gap of a main semiconductor at room temperature.

FIG. 5 is an equivalent circuit of a soft X-ray detector according to the present invention.

FIG. 6 (a) is a 1500 mm thick B filter,
(B) is a figure which shows each spectral transmittance of C filter of thickness 1000 degrees.

FIG. 7 is a graph showing a change in an absorption coefficient of the substance shown in Configuration Example 6.

FIG. 8 is a diagram showing a configuration when a soft X-ray detector of the present invention is used for a soft X-ray microscope.

FIG. 9 is a cross-sectional view of a conventional CCD solid-state imaging device used for soft X-ray detection.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Photoelectric conversion layer 2 ... Surface electrode layer 3 ... Pixel electrode 4 ... Soft X-ray 11,12 ... Vacuum chamber 13,14 ... Window 15 ... Laser plasma light source 16 ... Condenser lens 17 ... Sample stage 18 ... Reflective objective lens 19 ... AMI

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Shoichiro Mochimaru 2-43-2 Hatagaya, Shibuya-ku, Tokyo O-limpus Optical Industry Co., Ltd. (56) References JP-A-3-73883 (JP, A) JP-A-3-276089 (JP, A) JP-A-52-2777 (JP, A) JP-A-60-78376 (JP, A) JP-A-63-224253 (JP, A) JP-A-4-130292 ( JP, A) (58) Fields surveyed (Int. Cl. ⁷ , DB name) G01T 1/20 G01T 1/24 H01L 31/09

Claims (4)

(57) [Claims] 1. A semiconductor device comprising: a surface electrode layer, a photoelectric conversion layer, and an electrode connected to the photoelectric conversion layer and detecting a charge generated in the photoelectric conversion layer, in order from a light incident side. A soft X-ray detector, wherein the photoelectric conversion layer and the surface electrode layer each have a thickness satisfying the following conditions (A) and (B). Condition _{(A) d A ≧ 0.183λ /} K A condition _{(B) d B ≦ 0.183λ /} K B where, d _A is the thickness of the photoelectric conversion layer, d _B is the thickness of the surface electrode layer, K _A is the absorption coefficient for light having a wavelength λ of a substance absorption coefficient for light having a wavelength λ of the material constituting the photoelectric conversion layer, K _B is constituting the surface electrode layer. 2. The following condition (C) is set on the incident side of the surface electrode layer.
2. The soft X-ray detector according to claim 1, wherein a filter for shielding visible light having a thickness d _C satisfying the following is provided. Condition (C) d _C ≧ 0.366 / (K _VF / λ _V −K _XF /
λ _X ) where K _VF is the absorption coefficient of the material constituting the filter for visible light of wavelength λ _V , and K _XF is the absorption coefficient of the material constituting the filter for soft X-rays of wavelength λ _X. 3. The soft X-ray detector according to claim 2, wherein the filter has a thickness d _C satisfying the following condition (D). Condition (D) d _C ≦ 0.183λ _X / K _XF 4. A surface electrode layer, a photoelectric conversion layer, and a semiconductor detector having an electrode connected to the photoelectric conversion layer and detecting a charge generated in the photoelectric conversion layer, in order from a light incident side. Wherein the photoelectric conversion layer and the surface electrode layer each have a thickness satisfying the following conditions (E), (F) and (G):
Line detector. Condition (E) d _E ≧ 0.183λ _X / K _XE Condition (F) d _F ≧ 0.366 / (K _V / λ _V −K _X /
λ _X ) Condition (G) d _F ≦ 0.183 λ _X / K _X where d _E is the thickness of the photoelectric conversion layer, d _F is the thickness of the surface electrode layer, and K _XE is the material of the photoelectric conversion layer. soft X of the wavelength λ _X
K _V is the absorption coefficient of the material constituting the surface electrode layer for visible light of wavelength λ _V , and K _X is the absorption coefficient of the material constituting the surface electrode layer for soft X-rays of wavelength λ _X.