KR20070106214A - Sensor for both ultraviolet rays and visible rays - Google Patents

Abstract

A sensor for detecting various wavelength is provided to simultaneously defect different wavelength regions as a reverse bias increases by including different band gaps in a single device. A sensor for detecting various wavelength has a structure in which a first light absorbing layer(13), a second light absorbing layer(14), and electrode layers(16,18) are sequentially formed on a substrate. The sensor is a semiconductor light receiving device detecting different wavelength regions as the bias of the electrode layer increases in a single device. The electrode layers are formed in some region of the second light absorbing layer. The substrate is selected from a group consisting of sapphire, AlN, GaN, SiC, Si, GaAs, and glass.

Description

Sensor for both ultraviolet rays and visible rays}

1 is a cross-sectional view of a conventional Schottky junction ultraviolet sensing element,

2 is a plan view of the ultraviolet sensing element shown in FIG.

3 is a cross-sectional view of an ultraviolet sensing element in which a second electrode layer is formed on a high temperature buffer layer;

4 is a plan view of the ultraviolet sensing element shown in FIG.

5 and 6 are cross-sectional views of a conventional ultraviolet sensing device showing the depletion layer expansion,

7 is a cross-sectional view of a sensor according to a first embodiment of the present invention;

8 is a plan view of the sensor shown in FIG.

9 is a cross-sectional view of a sensor according to a second embodiment of the present invention;

10 is a plan view of the sensor shown in FIG. 9;

11 is a cross-sectional view of a sensor according to a third embodiment of the present invention;

12 is a plan view of the sensor shown in FIG.

13 is a cross-sectional view of a sensor according to a fourth embodiment of the present invention;

14 is a plan view of the sensor shown in FIG.

15 is a cross-sectional view of a sensor according to a fifth embodiment of the present invention;

16 is a plan view of the sensor shown in FIG. 15;

17 is a cross-sectional view of a sensor according to a sixth embodiment of the present invention;

18 is a plan view of the sensor shown in FIG. 17;

19 is a cross-sectional view of a sensor according to a seventh embodiment of the present invention;

20 is a plan view of the sensor shown in FIG. 19;

21 is a cross-sectional view of a sensor according to an eighth embodiment of the present invention;

22 is a plan view of the sensor shown in FIG. 21 of the present invention;

23 is a cross-sectional view of a sensor according to a ninth embodiment of the present invention;

24 is a plan view of the sensor shown in FIG. 23;

25 is a cross-sectional view of a sensor according to a tenth embodiment of the present invention;

FIG. 26 is a plan view of the sensor shown in FIG. 25;

27 is a cross-sectional view of a sensor according to an eleventh embodiment of the present invention;

28 is a plan view of the sensor shown in FIG. 27;

29 is a cross-sectional view of a sensor according to a twelfth embodiment of the present invention;

30 is a plan view of the sensor shown in FIG. 29;

31 is a cross-sectional view of a sensor according to a thirteenth embodiment of the present invention;

32 is a plan view of the sensor shown in FIG. 31;

33 is a schematic diagram showing expansion of a depletion layer according to bias application;

34, 35, 36, 37 is a reaction diagram showing that after forming the light absorption layer having a different band gap can be detected by selecting the UVA, UVB, UVC wavelength band according to the increase of reverse bias,

FIG. 38 shows the measured reactivity measured by using GaN as the light absorption layer 1 and changing the wavelength range detected by increasing the reverse bias using AlGaN of 20% Al as the light absorption layer 2.

* Explanation of symbols for main parts of the drawings

10 substrate 11 low temperature buffer layer

12 high temperature buffer layer 13 light absorption layer 1

14: light absorbing layer 2 15: light absorbing layer 3

16: first electrode layer 17: pad layer

18: second electrode layer 19: intermediate buffer layer

20: capping layer 21: depletion layer region 1

22: depletion layer region 2 23: depletion layer region 3

24: two-dimensional electron gas layer 25: two-dimensional electron gas concentration lowering layer

26: p-type AlGaN layer 27: intrinsic layer

The present invention relates to a sensor for detecting visible and ultraviolet rays, and in particular, a structure in which the light absorbing layer is formed to have different band gaps, and the visible light and the wavelength of the same element can be detected at the same time as the reverse voltage increases. It relates to a sensor for detecting ultraviolet rays.

Ultraviolet rays with a wavelength of 400 nm or less are divided into several bands for each wavelength. The UV-A region is 320 nm-400 nm, and more than 98% of the sunlight reaching the earth's surface is the UV-A region. UV-A affects blackening and skin aging of human skin. The UV-B area is 280nm-320nm, and only about 2% of sunlight reaches the surface of the earth. It has a very serious effect on the human body such as skin cancer, cataracts and erythema. UV-B is mostly absorbed by the ozone layer, but recently, the amount reaching the surface of the earth due to the destruction of the ozone layer is increasing and the area is increasing, which is a serious environmental problem. UV-C is between 200nm and 280nm, all of which comes from sunlight is absorbed into the ozone layer and the atmosphere and hardly reaches the earth's surface. This area is widely used for sterilization. One of the quantified effects of ultraviolet rays on the human body is the UV Index defined by the amount of UV-B incident.

Ultraviolet rays can be detected by using a photo multiplier tube (PMT) or a semiconductor device. Since semiconductor devices are cheaper and smaller than PMT, most of them use a lot of semiconductor devices in recent years. In the semiconductor device, although the energy band gap has a small energy band gap such as GaN, SiC, etc., which is suitable for ultraviolet detection, Si is widely used. Among the devices based on GaN, Schottky junction type, MSM (metal-semiconductor-metal) type and PIN type devices are mainly used. Schottky junction type devices are preferred because of their simple process. .

The structure of a conventional Schottky junction UV sensing element is shown in FIGS. 1 and 2. As can be seen from FIGS. 1 and 2, a conventional Schottky junction UV sensor first grows a GaN and SiC layer on a substrate using MOCVD or MBE. In the substrate 10 to be used, sapphire is most often used for GaN layer growth, Si, GaAs, SiC, etc. are used, and glass is rarely used.

In the case of a sapphire substrate is grown on the (0001) plane, if the growth immediately due to the difference in the lattice constant between GaN and sapphire cracks do not grow properly layer. Therefore, after the low temperature buffer layer 11 is grown at a temperature lower than the normal growth temperature of 500 ~ 600 ℃, the growth temperature is raised to grow a layer required for the device. The low temperature buffer layer 11 mainly grows GaN or AlN and has a thickness of 0.1 μm or less.

After growing the low temperature buffer layer, the GaN layer is mainly grown to grow the high temperature buffer layer 12 thereon. Generally, about 0.5 to 2 μm should be grown to reduce the influence of defects caused by the substrate and the buffer layer, resulting in good crystallinity of the layer. Lose. The high temperature buffer layer 12 may be used as a light absorption layer, and the high temperature buffer layer 12 may be artificially doped with a dopant such as Si to maintain the doping concentration of the layer as n-type.

After the growth of the high temperature buffer layer 12, the light absorbing layer 1 (13) is grown, which is grown by varying the composition of the layer according to the wavelength of light to be absorbed. For example, to detect a UV-B region, an AlGaN layer containing about 20% of Al is grown, and an AlGaN layer containing about 45% of Al is grown to detect a UV-C area. In the case where the high temperature buffer layer is GaN and the light absorbing layer is AlGaN, if the Al composition is high, cracks may occur during or after the growth due to the lattice constant difference, thereby preventing the device operation. Another intermediate buffer layer 19 may be inserted. The intervening intermediate buffer layer 19 grows an AlGaN or AlN layer to lower the growth temperature or grow a thin layer (<0.1um) having a larger Al composition than the light absorbing layer. The doping concentration of the light absorbing layer has a lower doping concentration 1E17cm-efficient as possible, while maintaining as large as n- type ^- if the AlGaN layer to be maintained at ³ or less gatgido a doping concentration of 1E18cm ^-3.

After the MOCVD growth, the wafer is first formed with the second electrode layer 18, which is formed directly on the light absorbing layer 1 (13), or the light absorbing layer 1 (13) is etched as shown in FIGS. It may be formed in the high temperature buffer layer 12. When the ohmic junction is formed in the high temperature buffer layer 12, the high temperature buffer layer 12 is formed to have a higher doping concentration than the light absorbing layer 1 (13), and thus the ohmic bonding characteristic is good, and the light absorbing layer is AlGaN and it is difficult to secure the ohmic bonding characteristic. In this case, an AlGaN layer having a lower Al composition than a GaN or light absorbing layer may be formed in the high temperature buffer layer 12, and an ohmic junction layer may be formed thereon.

As the metal for forming the ohmic junction, Ti / Al and Cr / Ni / Au are mainly used. In the case of Ti / Al, Ti (<500Å) / Al (> 3000Å) thickness is formed, and metal is deposited, followed by heat treatment at a temperature of> 400 ° C. for a suitable time in a mixed gas atmosphere containing nitrogen or nitrogen to form an ohmic junction. Form. After the ohmic junction layer is formed, the first electrode layer 16 is formed on the light absorbing layer. The metals mainly used are Ni, Pt, Ru, Au, and the like. In the case of the Schottky junction sensing device, ultraviolet light transmittance of the Schottky junction layer is an important item because light must pass through the Schottky junction layer and enter the light absorbing layer. Therefore, most of the metal thickness is formed by depositing less than 500Å. Also, in order to improve electrical and reliability characteristics, an oxide may be formed by heat treatment after metal deposition. That is, a lot of improved characteristics such as NiO _x and RuO _x have been reported. The heat treatment temperature is variously performed by the metal and the process, and is mainly performed at about 300 ° C. ITO is often used to further form a light transmissive conductive layer on the Schottky junction layer to improve electrical properties. In the case of the Schottky type, after forming the Schottky bonding layer, a thick layer of gold (Au) is deposited on the Schottky bonding layer for wire connection with an external electrode to form a pad layer 17. Mainly Ni / Au or Cr / Ni / Au is used. Since the region in which the Schottky pad layer is formed does not transmit light and thus does not act as a Schottky bonding layer, the region of the Schottky pad layer should be reduced to the minimum space for the bonding wire.

After the formation of the Schottky pad layer, the back side of the substrate is lapping / polishing to make the entire thickness about 100um and then scribe / brake to separate into individual devices. The separated individual device is mounted in a TO-CAN type package or an SMD type package to operate as a sensing device.

In the Schottky junction sensing element, a depletion layer is formed on the light absorbing layer in contact with the Schottky junction layer due to the Schottky barrier effect by the Schottky junction layer. In the depletion layer, there are no electrons or holes that can move charges, and currents flow as electrons or holes generated by light move to the Schottky junction layer and the ohmic junction layer. That is, when the sensing element is exposed to ultraviolet rays, ultraviolet rays pass through the Schottky junction layer and enter the depletion layer, and the incident ultraviolet rays generate electrons / holes, and electrons move into the ohmic junction layer and holes move to the Schottky junction layer. And the current is sensed to measure the amount of incident light of ultraviolet rays. As the doping concentration of the light absorbing layer is lower, the thickness of the depletion layer is increased and the amount of electrons / holes generated by light increases, so it is preferable to reduce the doping concentration of the possible depletion layer. In addition, since the ultraviolet light is transmitted through the Schottky bonding layer, the transmittance of the Schottky bonding layer should be good, but the thickness of the metal should be thin or a metal having good transmittance should be used. In addition, since the higher the potential barrier by the Schottky junction has a stable electrical characteristics to form a Schottky junction layer in consideration of these characteristics overall. In general, the bias is not applied externally during the operation of the device, but the bias is also applied in the reverse direction to increase the light conversion efficiency. When the bias is applied in the reverse direction, the thickness of the depletion layer increases, but since the two-dimensional electron gas layer having a high doping concentration is formed between the GaN layer and the AlGaN layer, which is a heterojunction structure, the depletion layer does not expand.

5 and 6 are shown for depletion layer expansion. 5 shows that the single light change efficiency is increased by increasing the thickness of the depletion layer, and FIG. 6 shows that the two-dimensional electron gas layer 24 is formed by the lattice mismatch between the intermediate buffer layer 19 and the light absorbing layer 13. The two-dimensional electron gas layer 24 is formed and serves to prevent the depletion layer from expanding upon bias application. Therefore, when the negative bias is applied to the Schottky junction layer and the positive bias is applied to the ohmic junction layer, the thickness of the depletion layer is increased to increase the single light change efficiency. When the sensing element is packaged in the TO-CAN type or the SMD type, the window must be made of a material that transmits ultraviolet rays, and quartz is mainly used. Or it may be composed of an encapsulrant of Si series.

In the conventional Schottky junction sensing device, when the GaN layer and the AlGaN layer, which are heterojunction structures, are formed by different lattice constant differences between the GaN layer and the AlGaN layer, between the GaN layer and the AlN layer, or between the AlN layer and the AlGaN layer, Because the high concentration of two-dimensional electron gas layer is formed to prevent the depletion of the depletion layer due to bias application, the depletion layer does not expand even when the bias is increased, so it only stays in the two-dimensional electron gas layer. Seems.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a semiconductor device capable of simultaneously detecting different wavelength regions in a single device.

In order to achieve the above object, in the structure in which the AlGaInN layers having different band gaps on the substrate are formed as light absorption layers, the light absorption layer is formed to increase the band gap from the substrate, and the semiconductor light receiving element having the electrode layers formed thereon. According to the increase of the reverse voltage, a sensor for detecting visible light and ultraviolet light, which enables detection of different wavelength regions in one device, is provided.

Hereinafter, with reference to the accompanying drawings, preferred embodiments that do not limit the present invention will be described in detail.

7 and 8 illustrate a sensor according to a first embodiment of the present invention, which is initially formed as the reverse bias increases in a structure in which the light absorption layers 13, 14, and 15 are formed to have different band gaps. The depletion layer extends to the light absorbing layer having different band gaps to detect different wavelength regions.

In the process technology of the present invention, the substrate 10 mainly uses sapphire, but AlN, GaN, SiC, Si, GaAs, glass, or the like may also be used. In the case of a sapphire substrate having a diameter of 2 inches, the thickness is 300 to 450 um, and a (0001) plane is mainly used as a growth plane, and a substrate given a tilt is also used to improve the surface of the light absorbing layer.

As a device for growing on the substrate 10, mainly MOCVD, MBE, HVPE and the like are used. In the case of MOCVD, after the substrate 10 is mounted, the temperature is raised to 1,000 ° C. or more to perform a thermal cleaning process to remove impurities from the surface of the substrate 10, and then grow. First, the low temperature buffer layer 11 is grown. That is, after lowering the growth temperature of the MOCVD to 500 ~ 600 ℃, to grow a low temperature buffer layer 11 to a thickness of 200 ~ 500Å, GaN or AlN is grown. The reason why the low temperature buffer layer 11 is grown is to solve this problem because crystal lattice cannot be grown because the lattice constant between the substrate 10 and other layers grown thereon is different.

After the growth of the low temperature buffer layer 11 grows the light absorption layer 1 (13) between the growth temperature of 1,000 ~ 1200 ℃. The light absorbing layer 1 (13) can be used as a high temperature buffer layer, and mainly grows a GaN or AlGaN layer, and generally has a thickness of 0.5 to 3 μm and is doped to n-type even without artificially doping or doping. Doping concentration is maintained at about 1E16 ~ 5E18 cm-3.

The light absorbing layer 2 (14) is grown on the light absorbing layer 1 (13), and the light absorbing layer 2 (14) grows an InGaN layer or an AlGaN layer with a thickness between 10 nm and 500 nm, and less than 1E18 cm-3. Grow to have a doping concentration of. In the case where the InGaN layer is used as the light absorption layer, the In composition can be increased to detect the wavelength of the visible light region. For example, when the InGaN layer having the 400 nm wavelength is used as the light absorbing layer by adjusting the In composition, detection is possible from the 400 nm wavelength. In the case where the light absorbing layer 2 (14) is AlGaN and the light absorbing layer 1 (13) is GaN, if the thickness is thick due to the lattice constant difference, cracks are generated, and thus the thickness of the AlGaN layer is limited. For example, in the case of AlGaN layer having 20% Al composition, if it grows more than 0.1um, crack occurs. Therefore, in order to prevent this, an intermediate buffer layer 19 may be inserted between the light absorbing layer 1 (13) and the light absorbing layer 2 (14), which is shown in FIG.

As the intermediate buffer layer 19, an AlN or AlGaN layer is mainly grown and formed to have a thickness of 50 to 500 mW. The growth temperature may be at a low temperature of 500 ~ 600 ℃, or at a high temperature of 900 ~ 1,100 ℃. If a high concentration of the two-dimensional electron gas layer is formed due to the different lattice constant difference between the light absorbing layer 1 (13) and the light absorbing layer 2 (14), the light absorbing layer 1 (13) or the light is not expanded. A two-dimensional electron gas concentration reducing layer 25 must be formed in absorbing layer 2 (14). The two-dimensional electron gas concentration reducing layer 25 may gradually increase the band gap from the band gap of the light absorbing layer 1 (13) to the band gap of the light absorbing layer 2 (14), or the light absorbing layer 1 (13) and the light absorbing layer 2 ( The two-dimensional electron gas concentration reducing layer 25 can be formed by adjusting the doping concentration at the interface of 14). Alternatively, at the interface between the light absorbing layer 1 (13) and the light absorbing layer 2 (14), the doping concentration of the light absorbing layer 1 (13) is equal to or higher than that of the light absorbing layer 2 (14) to form the two-dimensional electron gas concentration reducing layer 25. can do. When the AlGaN light absorbing layer 3 (15) is grown on the light absorbing layer 2 (14), two-dimensional electrons are applied in the same manner as the light absorbing layer 1 (13) and the light absorbing layer 2 (14) interface to suppress the formation of the two-dimensional electron gas layer at the interface. The gas concentration reducing layer 25 is formed.

After the growth of the light absorbing layer, an AlGaN layer having a p-type doping concentration having the same or greater band gap as the light absorbing layer is grown to become a PIN type light receiving device. If the PIN type light receiving element is formed to have different bandgaps in the intrinsic layer 27, different wavelengths can be detected as the reverse bias increases. 50-300 nm thick p-type doped AlGaN layer 26 is formed on the intrinsic layer 27. At this time, the band gap of the p-type AlGaN layer 26 minimizes the influence of the absorbed wavelength. It must be equal to or larger than the light absorption layer in order to Such a PIN type light receiving element is shown in FIGS. 9 and 10.

After the light absorbing layer or the p-type AlGaN layer 26 is grown, the capping layer 20 may be grown as in the embodiments of FIGS. 13 and 14, and the capping layer 20 is between 1 and 10 nm, and the light absorbing layer or A layer having a smaller bandgap than a p-type AlGaN layer should be used to form a good ohmic electrode layer. The growth temperature of the capping layer 20 may be grown between 700 ~ 1200 ℃. The thickness of the capping layer 20 should be less than 1/10 of the thickness of the space charge region (SCR) region formed in the light absorbing layer to affect the optical reactivity of the light absorbing layer by 10% or less.

After the capping layer 20 is finished, the grown sample is taken out of the growth apparatus, washed with HF solution, and then proceeds to the chip manufacturing process. First, a pattern is formed on the capping layer 20 by a photoresist. When the capping layer 20 is not present, a pattern may be formed on the light absorbing layer using a photoresist. The second electrode layer 18 is formed by depositing Ti / Al metal using an e-beam or a thermal evaporator, and then removing the photoresist. Metals mainly used to form ohmic junctions in N-type GaN or AlGaN layers include Ti / Al, Cr / Ni / Au, and the deposition thickness is about Ti (100 to 500Å) and Al (5,000). Deposit about ~ 10,000 정도). In order to secure the ohmic bonding properties of the deposited second electrode layer 18, a heat treatment process is performed. Generally, heat treatment is performed for several minutes in a nitrogen or general air atmosphere at a temperature of about 500 ° C. Some metals, such as Cr / Ni / Au, can secure ohmic bonding properties even without heat treatment.

Although the second electrode layer 18 is formed on the capping layer 20 as in the embodiments of FIGS. 13 to 16, when the ohmic bonding characteristics are difficult to obtain in the capping layer 20, the second electrode layer 18 is different from that of the first embodiment of FIG. 7. Likewise, the light absorbing layer 2 (14) and the light absorbing layer 3 (15) may be etched and formed on the light absorbing layer 1 (13). Etching mainly uses a dry etching method using ICP.

FIG. 11 illustrates a case in which an intermediate buffer layer 19 is inserted between the light absorbing layer 1 (13) and the light absorbing layer 2 (14) in the structure shown in FIG. 7. After forming the second electrode layer 18, Ni, Pt, Pd, Au, etc. may be formed on the light absorption layer, the capping layer 20, or the p-type AlGaN by using an e-beam or a thermal evaporator to form a pattern using a photoresist. The thin layer is deposited on the layer 26 and then the photoresist is removed to form the first electrode layer 16. In the case of the PIN type, ohmic properties are formed on the p-type layer. For example, in the case of Ni metal, it is difficult to obtain ohmic properties on n-GaN, but it is known as a metal that is easy to obtain ohmic properties on p-GaN. At this time, the thickness of the metal to be deposited is 100 kPa or less in consideration of the transmittance. The first electrode layer for the Schottky or p-layer ohmic junction is deposited and then heat treated. When the first electrode layer is deposited and then subjected to heat treatment, the temperature is lower than that at which the second electrode layer 18 is formed. When Ni is deposited in the short group type, heat treatment in an oxygen atmosphere may form NiOx or use Ni without heat treatment. After the Schottky metal or p-layer ohmic metal is formed, a pattern is formed with a photoresist to form a pad layer, and then Ni / Au, Pt / Au, etc. are deposited using an e-beam or a thermal evaporator, and then a photoresist To form a pad layer. The deposition thickness is about Ni, Pt (<500Å), Au (> 5,000Å) and no additional heat treatment. Once formed to the pad layer, SiO ₂ is used to prevent reflection of incident ultraviolet rays. In some cases, a thickness suitable for the wavelength is deposited.

After inspecting the characteristics of the device in the wafer state, the good and bad devices are distinguished by ink marks, and then the back surface of the substrate 10 is ground / wrapped / polished to form a total thickness of about 100 μm, followed by individual chips by scribe & break process. Separate the process into a package process. In the package process, the chips manufactured in the TO-CAN type or the SMD type package are die-bonded, and the pad layer 17 and the second electrode layer 18 are made using the anode and cathode electrodes of the package and Au or Al wire, respectively. Wire bond. The final assembly is then encapsulant or glass to completely separate the chip from the external environment.

13 and 14 show a Schottky type having a structure of light absorbing layer 1 (13), light absorbing layer 2 (14), and light absorbing layer 3 (15), wherein the first electrode layer 16 is formed on the capping layer 20. It is a case where it joins and the 2nd electrode layer 18 is made to be an ohmic junction.

15 and 16 are similar to the sensors of the embodiment shown in FIGS. 13 and 14, but the intermediate buffer layer 19 is inserted between the light absorbing layer 1 (13) and the light absorbing layer 2 (14). .

17 and 18 are formed on the light absorbing layer 2 (14) so that the first electrode layer 16 is a Schottky junction in the structure consisting of the light absorbing layer 1 (13) and the light absorbing layer 2 (14), the second electrode layer 18 It is a structure formed on the light absorption layer 1 (13) to be ohmic bonded to the ().

19 and 20 are similar to the embodiment shown in FIGS. 17 and 18, but the intermediate buffer layer 19 is inserted between the light absorbing layer 1 (13) and the light absorbing layer 2 (14).

21 and 22 show that the first electrode layer 16 is Schottky bonded on the capping layer 20 in the structure formed of the light absorption layer 1 (13) and the light absorption layer 2 (14) or the capping layer 20, and the second electrode layer. (18) is a structure formed to be an ohmic junction.

23 and 24 are similar to those of FIGS. 21 and 22, but the intermediate buffer layer 19 is inserted between the light absorption layer 1 (13) and the light absorption layer 2 (14).

25 and 26 show that the first electrode layer 16 is formed on the light absorbing layer 3 (15) in a structure formed of the light absorbing layer 1 (13) and the light absorbing layer 3 (15) so that the second electrode layer 18 is formed. This is the case where the ohmic junction is formed on the light absorption layer 1 (13).

27 and 28 are similar to those of FIGS. 25 and 26, but the intermediate buffer layer 19 is inserted between the light absorption layer 1 (13) and the light absorption layer 3 (15).

29 and 30, in the structure in which the capping layer 20 is formed on the light absorbing layer 1 (13) and the light absorbing layer 3 (15), the first electrode layer 16 is connected to the Schottky junction and the second electrode layer ( 18) is a case where the ohmic junction is formed on the capping layer 20.

31 and 32 are similar to the embodiment shown in FIGS. 29 and 30, but the intermediate buffer layer 19 is inserted between the light absorption layer 1 (13) and the light absorption layer 3 (15).

33 is a schematic diagram showing the expansion of the depletion layer according to the bias application in the sensor of the present invention. As the depletion layer region 21 initially formed extends through the two-dimensional electron gas concentration lowering layer 25 as the reverse bias increases, the light absorption layers 14 and 13 having different band gaps can detect different wavelength regions. It is shown. The depletion layer can be extended to the light absorbing layer in the structure in which the two-dimensional electron gas concentration reducing layer 25 is formed between the light absorbing layer 2 (14) and the light absorbing layer 1 (13).

34 to 37 is a reaction diagram showing that the UVA, UVB, UVC wavelength bands can be selected and detected as the reverse bias increases after forming the light absorption layer having a different band gap in the present invention. In addition, when the InGaN layer having a band gap in the visible light region is used as the light absorption layer, the detection region may be extended to visible light.

FIG. 34 shows the UVC wavelength region at 0V, the UVB wavelength region at -2V, and the UVA wavelength region at -4V, after the light absorption layers 13, 14, and 15 have different bandgaps. The value is shown. FIG. 35 is a reaction diagram showing that after forming the light absorption layers 13 and 14 having different band gaps, the UVB wavelength region is detected at 0V and extends to the UVA wavelength region at -2V. 36 is a reaction diagram illustrating the detection of the UVC wavelength region at 0V and the UVB wavelength region at -2V after formation of the light absorption layers 14 and 15 having different bandgaps. FIG. 37 is a reaction diagram illustrating the detection of the UVC wavelength region at 0V and the UVA wavelength region at -2V after formation of the light absorption layers 13 and 15 having different bandgaps.

38 shows GaN used as the light absorbing layer 1 (13) and AlGaN of 20% Al as the light absorbing layer 2 (14). In the 0-bias, the reverse bias is increased while detecting the UVB wavelength region, and thus the reactivity characteristic of detecting the UVA wavelength region is shown.

As described above, the present invention is manufactured in the same manner as the conventional operation and separated into individual chips to be packaged and operated in TO-CAN or SMD type. Ultraviolet rays incident at the initial zero bias between the anode and cathode electrodes are absorbed in a depletion layer formed in the light absorption layer below the first electrode layer 16 to generate electrons and holes, which move to the cathode and anode electrodes, respectively. As it flows, it detects the amount of incident light to detect the primary wavelength region, and as the reverse bias increases, the depletion layer extends past the two-dimensional electron gas concentration lowering layer 25 in the light absorption layer, thereby detecting the secondary wavelength region. You can do it.

As described above, the present invention has the effect of having a single sensor exhibiting the function of several sensors because it can simultaneously detect different wavelength ranges as the reverse bias increases by having different band gaps as light absorption layers in a single device. Have

Claims (16)

A semiconductor light-receiving device for detecting a different wavelength region according to an increase in bias of an electrode layer in a single device having a light absorption layer 1, a light absorption layer 2, and an electrode layer sequentially on a substrate; The light absorption layer 1 is Al _x Ga _{1 -} consists of a _x N (0≤x≤1) layers, the light absorbing layer 2 is Al _y Ga _{1 -} consists of _y N (x≤y≤1) layer, a light Sensor for detecting visible and ultraviolet light, characterized in that the electrode layer is formed on a portion of the absorption layer 2. The method according to claim 1, The substrate is a sensor for detecting visible and ultraviolet light, characterized in that selected from the group consisting of sapphire, AlN, GaN, SiC, Si, GaAs and glass. The method according to claim 1, The doping concentration of the light absorbing layer 1 at the interface between the light absorbing layer 1 and the light absorbing layer 2 is the same or higher than the doping concentration of the light absorbing layer 2, the sensor for detecting visible and ultraviolet light. The method according to claim 1, The sensor for detecting visible and ultraviolet light, characterized in that the Al composition of the light absorbing layer 2 increases from the interface where the light absorbing layer 1 and the light absorbing layer 2 is in contact with the electrode layer. The method according to claim 1, Sensor for detecting visible light and ultraviolet light, characterized in that the light absorption layer 2 has a thickness of 10 nm ~ 500 nm. The method according to claim 1, The electrode layer is selected from a metal or a conductive oxide including Ni, Pt, Pd, Cr, Au, Al, Ti, and the electrode layer is for detecting visible light and ultraviolet light, characterized in that to form a Schottky junction with the light absorption layer 2 sensor. The method according to claim 1, The electrode layer is composed of p-type Al _x Ga _{1 - x} N (0≤x≤1) to form a pn junction with the light absorption layer 2, the sensor for detecting visible and ultraviolet light. A semiconductor light receiving device that sequentially detects different wavelength regions according to an increase in the bias of an electrode layer in a single device in a structure consisting of a buffer layer, a light absorbing layer 1, a light absorbing layer 2 having an energy band gap larger than that of the light absorbing layer 1, and an electrode layer; The buffer layer is composed of an AlGaInN layer, the light absorbing layer 1 is composed of an AlGaInN layer, the light absorbing layer 2 is composed of an AlGaInN layer, visible light and ultraviolet light, characterized in that the electrode layer is formed in a portion above the light absorbing layer 2 Sensor for detection. The method according to claim 8, The substrate is a sensor for detecting visible and ultraviolet light, characterized in that selected from the group consisting of sapphire, AlN, GaN, SiC, Si, GaAs and glass. The method according to claim 8, The electrode is a sensor for detecting visible and ultraviolet light, characterized in that the ohmic junction formed in a portion of the buffer layer, the light absorption layer 1 or the light absorption layer 2. The method according to claim 8, The buffer layer, the light absorption layer 1, the light absorption layer 2 is a sensor for detecting visible and ultraviolet light, characterized in that all formed in the n-type. The method according to claim 8, The sensor for detecting visible and ultraviolet rays, characterized in that the doping concentration of the light absorption layer 1 is formed at the same or higher than the doping concentration of the light absorption layer 2 at the interface where the light absorption layer 1 and the light absorption layer 2 contact. The method according to claim 8, The sensor for detecting visible and ultraviolet light, characterized in that the energy band gap of the light absorbing layer 2 increases from the interface where the light absorbing layer 1 and the light absorbing layer 2 in contact with each other. The method according to claim 8, Sensor for detecting visible light and ultraviolet light, characterized in that the light absorption layer 2 has a thickness of 10 nm ~ 500 nm. The method according to claim 8, The electrode layer is selected from a metal or a conductive oxide including an electrode layer Ni, Pt, Pd, Cr, Au, Al, Ti, and the electrode layer forms a Schottky junction with the light absorption layer 2 Sensor for detection. The method according to claim 8, The electrode layer is composed of p-type Al _x Ga _{1 - x} N (0≤x≤1) to form a pn junction with the light absorption layer 2, the sensor for detecting visible and ultraviolet light.

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