JP2008153606A - Light emitting element of mos structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting element of MOS structure capable of continuous oscillation action. <P>SOLUTION: The light emitting element 1 having MOS structure includes a MOS transistor 2 and a ballistic electron source 3 arranged right under the MOS transistor 2. The MOS transistor 2 is a p-channel type MOS transistor. Holes are injected from the MOS transistor 2 to a floating gate 10 by a tunnel current, and electrons are injected from the ballistic electron source 3 to the floating gate 10. Thereby the electrons and the holes are continuously recombined and light is emitted in the floating gate 10, and continuous oscillation action is realized. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light emitting element having a MOS structure that can be used as a light source for optical interconnection, a light source for display, a light source for illumination, a light source for pickup, and the like.

  Conventional light sources include LEDs and LDs based on direct transition type compound semiconductors, and materials such as GaN, GaAs, and InP are used depending on the wavelength. With these materials, it is difficult to monolithically integrate a current integrated electronic circuit chip mainly composed of silicon and a light source. For example, the method of Toyohashi University of Technology reported that Nikkan Kogyo Shimbun (2006/6/29) Business & Technology "Toyohashi University of Technology integrates embedded technology IC and light-emitting element" is used on a silicon substrate for monolithic integration. In addition, a technique of epitaxially growing a transition type semiconductor directly by a dislocation-free growth technique of Si / III-VN mixed crystal is used (see Non-Patent Document 1).

  As a technique for emitting silicon itself, a large number of documents have been published so far, and it has been found that light emission using porous silicon emits light very efficiently (for example, Non-Patent Document 2). Non-Patent Document 3, and Patent Documents 1 to 3).

In addition, a technology has been reported in which silicon nanoparticles are contained in a floating gate and a silicon circuit having a MOS structure similar to a flash memory is used to emit silicon nanoparticles by injecting electrons and holes alternately by reversing the gate voltage. (For example, refer nonpatent literature 4).
JP 08-139359 A "Method for Manufacturing Porous Silicon Light-Emitting Element" Japanese Patent Application Laid-Open No. 08-046245 “Method of forming porous silicon light emitting layer” Japanese Patent Laid-Open No. 05-198839 “Silicon-integrated integrated light-emitting device and manufacturing method thereof” Ota, Morisaki, Fumi, Ishiji, Furukawa, Yonezu, Wakahara, "Fabrication of MOSFETs and LEDs for Si / III-V-N optoelectronic integrated circuits," IEICE Technical Report, ED2006-33, pp. 73-78 (May, 2006) Journal of Applied Physics 98, 123509 (2005) Applied Physics Letters 87, 031107 (2005) RJ Walters et al., Nature materials, Vol. 4, No. 2 (2005)

  By the way, in the method of manufacturing a light emitting element by epitaxially growing a transition type semiconductor directly on a silicon substrate as in the technique described in Non-Patent Document 1, the manufacturing process is very complicated, and a compound semiconductor crystal device is manufactured. It must be introduced into the CMOS process, and there is no denying the possibility of causing contamination of the CMOS process equipment.

  In addition, the method itself for emitting porous silicon, such as the techniques described in Non-Patent Document 2, Non-Patent Document 3, and Patent Documents 1 to 3, has been studied for improving the luminous efficiency. A method for integrating the semiconductor integrated circuit into a silicon CMOS circuit has not been studied.

  Furthermore, although the method described in Non-Patent Document 4 has a very good affinity with the CMOS circuit, it emits light by reversing the polarity of the gate voltage, so that only a pulse oscillation operation can be obtained.

  The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a MOS structure light emitting device capable of continuous oscillation operation.

  In order to solve the above problems, a light emitting element having a MOS structure according to the first aspect of the present invention is formed in a MOS transistor and a gate insulating film between a gate electrode and a channel region of the MOS transistor, And a floating gate including a material capable of emitting light by recombination, and a ballistic electron source disposed immediately below the MOS transistor, injecting holes from the MOS transistor to the floating gate, and the ballistic electron source The gist is that light is emitted in the floating gate by injecting electrons into the floating gate.

  According to this aspect, holes are injected from the MOS transistor to the floating gate by a tunnel current, and electrons are injected from the ballistic electron source to the floating gate. Thereby, electrons and holes are continuously recombined in the floating gate to emit light, so that continuous oscillation operation is realized.

  In order to solve the above problems, a MOS structure light emitting device according to a second aspect of the present invention includes a MOS transistor, a ballistic electron source disposed immediately below the gate electrode of the MOS transistor, and a gate electrode of the MOS transistor. A floating gate formed in a gate insulating film between the ballistic electron source directly below and the channel region and containing a material capable of emitting light by recombination of electrons and holes, and a hole is formed from the MOS transistor to the floating gate. The gist is to emit light in the floating gate by injecting and injecting electrons from the ballistic electron source to the floating gate.

  According to this aspect, holes are injected from the MOS transistor to the floating gate by a tunnel current, and electrons are injected from the ballistic electron source to the floating gate. Thereby, electrons and holes are continuously recombined in the floating gate to emit light, so that continuous oscillation operation is realized.

  In order to solve the above problems, a light emitting element having a MOS structure according to a third aspect of the present invention includes a first MOS transistor and a second MOS transistor, and one end side of which is a gate electrode and a channel of the first MOS transistor. It is located in the gate insulating film between the region and the other end side is located in the gate insulating film between the gate electrode and the channel region of the second MOS transistor, and the electrons and holes are recombined. Light is emitted in the floating gate by injecting electrons from the first MOS transistor to the floating gate and holes from the second MOS transistor to the floating gate. The gist is to make it.

  According to this aspect, the floating gate is shared by two MOS transistors, electrons are injected from the first MOS transistor to the floating gate with a tunnel current, and tunnel current is injected from the second MOS transistor to the floating gate. Inject holes. As a result, carrier distribution (charge distribution) is generated in the floating gate, so that diffusion current flows and electrons and holes move to the center of the floating gate, and electrons and holes are continuously recombined in the floating gate. The light is emitted and continuous oscillation operation is realized.

  The light emitting element having a MOS structure according to another aspect of the present invention is summarized in that the first MOS transistor is an n-channel MOS transistor and the second MOS transistor is a p-channel MOS transistor.

  According to this aspect, electrons can be efficiently injected from the n-channel MOS transistor to one end of the floating gate, and holes can be efficiently injected from the p-channel MOS transistor to one end of the floating gate by the tunnel current. improves. In this case, the first MOS transistor and the second MOS transistor can be constituted by one CMOS transistor.

According to another aspect of the present invention, there is provided a MOS structure light emitting device, wherein the potential applied to the substrate and gate electrode of the first MOS transistor is potential 1 and potential 2, respectively, and the gate electrode and substrate of the second MOS transistor When the potential applied to each is potential 3 and potential 4,
Potential 1 <potential 2 ≦ potential 3 <potential 4
The main point is to satisfy this relationship.

  According to this aspect, a potential difference in the direction in which carriers gather in the center occurs on the left and right of the floating gate, and in addition to the diffusion current, a drift current due to this potential difference flows, thereby further improving the light emission efficiency.

  According to another aspect of the present invention, there is provided a MOS light emitting device, wherein the MOS transistor includes a silicon substrate including a channel region, and a gate formed through a gate insulating film corresponding to the channel region on the substrate. The gist is to include an electrode and a source region and a drain region formed on both sides of the channel region on the silicon substrate.

  In the method of manufacturing a light emitting element by epitaxially growing a transition type semiconductor directly on a silicon substrate as in the technique described in Non-Patent Document 1, the manufacturing process is very complicated, and a compound semiconductor crystal device is formed by CMOS. It must be introduced into the process, and there is no denying the possibility of causing contamination of CMOS process equipment.

  In addition, the method itself for emitting porous silicon, such as the techniques described in Non-Patent Document 2, Non-Patent Document 3, and Patent Documents 1 to 3, has been studied for improving the luminous efficiency. A method for integrating the semiconductor integrated circuit into a silicon CMOS circuit has not been studied.

  On the other hand, according to this embodiment, the transistor is made of MOS-structure silicon, and a MOS-structure light-emitting element can be manufactured by a silicon-based device in a process compatible with the silicon CMOS process. Therefore, the light emitting element and the integrated electronic circuit chip (silicon CMOS circuit) can be monolithically integrated. Therefore, it is possible to realize a light emitting element having a MOS structure capable of continuous oscillation operation and monolithically integrated with a silicon CMOS circuit.

  A gist of a light emitting device having a MOS structure according to another aspect of the present invention is that the floating gate is formed of a material containing silicon nanoparticles.

  According to this aspect, the electrons and holes are continuously recombined in the floating gate containing the silicon nanoparticles, so that the silicon nanoparticles in the floating gate emit light continuously.

  The light emitting element of the MOS structure according to another aspect of the present invention is characterized in that the floating gate is formed of a direct transition semiconductor material.

  According to this aspect, electrons and holes are continuously recombined in the floating gate formed of the direct transition semiconductor material, so that light is emitted continuously in the floating gate. Luminous efficiency is improved by using a direct transition type semiconductor material as the material of the floating gate. In addition, the gate insulating film is formed in two parts: a first insulating film on the substrate side from the floating gate and a second insulating film on the gate electrode side from the floating gate. Since the transition type semiconductor is grown directly on the first insulating film to form the floating gate, the process is easier than growing the transition type semiconductor directly on the silicon substrate, and an insulating film material is selected. Thus, various direct transition semiconductor materials can be dealt with.

  A light emitting device having a MOS structure according to another aspect of the present invention uses an i-type semiconductor not doped with impurities as the material containing the silicon nanoparticles forming the floating gate or the direct transition semiconductor material. And

  In a general light emitting element using a PN junction, impurity doping is performed in order to manufacture a p-type semiconductor and an n-type semiconductor, so that carrier mobility is lowered and high-speed operation is hindered. On the other hand, according to this aspect, by using an i-type semiconductor (intrinsic semiconductor) that does not perform impurity doping as the material including the silicon nanoparticles forming the floating gate or the direct transition semiconductor material, Carrier mobility can be increased, and high-speed operation performance as a light source is improved.

  A gist of a light emitting element having a MOS structure according to another aspect of the present invention is that the MOS transistor is a p-channel MOS transistor.

  According to this aspect, holes can be efficiently injected from the p-channel MOS transistor to the floating gate by the tunnel current, and the light emission efficiency is improved.

  According to the present invention, it is possible to realize a light emitting element having a MOS structure capable of continuous oscillation.

Embodiments embodying the present invention will be described with reference to the drawings. In the description of each embodiment, similar parts are denoted by the same reference numerals, and redundant description is omitted.
(First embodiment)
FIG. 1 is a schematic diagram showing a schematic configuration of a light emitting device 1 having a MOS structure according to the first embodiment of the present invention. In the figure, in order to conceptually represent carrier injection, ● represents an electron, and ○ represents a hole.

  The light emitting element 1 having a MOS structure includes a MOS transistor 2 and a ballistic electron source 3 disposed immediately below the MOS transistor 2. The MOS transistor 2 used in the present embodiment is a p-channel MOS (p-MOS) transistor.

  The MOS transistor 2 includes an n-type silicon substrate 5 including a channel region 4, a gate electrode 7 formed through a gate insulating film 6 corresponding to the channel region 4 of the silicon substrate 5, and the silicon substrate 5. And p-type source region 8 and p-type drain region 9 formed on both sides of channel region 4.

  Further, the MOS transistor 2 includes silicon nanoparticles formed in a gate insulating film 6 between the gate electrode 7 and the channel region 4 of the silicon substrate 5 as a material capable of emitting light by recombination of electrons and holes. A floating gate 10 is formed.

  In the MOS transistor 2, the floating gate 10 is formed in the gate insulating film 6, and the gate insulating film 6 includes the first insulating film 6 a closer to the silicon substrate 5 than the floating gate 10 and the gate electrode 7 from the floating gate 10. The second insulating film 6b is divided into two parts. That is, the first insulating film 6a is formed on the silicon substrate 5, the floating gate 10 containing silicon nanoparticles is formed on the first insulating film 6a, and the second insulating film 6b is formed on the floating gate 10. In addition, a gate electrode 7 is formed on the second insulating film 6b.

  As described above, in the light emitting element 1 having the MOS structure according to the first embodiment, first, the ballistic electron source 3 made of porous silicon is formed on one surface of the silicon substrate 5. This ballistic electron source 3 is a layer of a ballistic electronic element made of porous silicon (silicon is made into a fine particle). When a high electric field is applied to this layer, electrons are ballistically emitted from the surface. It is configured as follows.

  A MOS transistor (MOS circuit) 2 is formed on the other surface of the silicon substrate 5. A floating gate 10 containing silicon nanoparticles is disposed between the gate electrode 7 and the channel region 4 of the MOS transistor 2. The first insulating film 6a above the channel region 4 is a silicon oxide film, and the thickness thereof is, for example, 3 nm to 10 nm, so that a tunnel current can flow. The gate length is, for example, 5 μm, and the size of 5 μm is a light emitting region. An ITO transparent electrode is used for the gate electrode 7 to facilitate external extraction of light.

  The gate electrode 7 is connected to the ground, and a high voltage is applied between the source electrode (not shown) on the p-type source region 8 and the drain electrode (not shown) on the p-type drain region 9 (between the source and drain). By applying the voltage, holes are injected from the MOS transistor 2 into the floating gate 10 by a tunnel current. At the same time, a high electric field is applied to the ballistic electron source 3 to inject electrons from the ballistic electron source 3 into the floating gate 10. As a result, the electron-holes recombine and emit light in the floating gate 10 containing silicon nanoparticles. In the floating gate 10, both holes and electrons disappear due to recombination, but the gate electrode 7 is grounded, a high voltage is applied between the source and the drain, and a high electric field is continuously applied to the ballistic electron source 3. In addition, holes are continuously injected from the MOS transistor 2 to the floating gate 10 by a tunnel current, and at the same time, electrons are continuously injected from the ballistic electron source 3 to the floating gate 10. As a result, the electron-holes continuously emit and recombine in the floating gate 10, and light is continuously emitted in the floating gate 10.

  The silicon nanoparticles contained in the floating gate 10 can be manufactured, for example, by anodizing polycrystalline silicon with nanocrystalline silicon having a diameter of about 3 nm. It is said that the physical properties of photon emission of visible light that cannot be seen in the normal bulk crystalline silicon state appear when the diameter of the silicon particles becomes silicon nanoparticles with a Bohr radius of 4 nm or less.

  According to 1st Embodiment which has the above structure, there exist the following effects.

  A hole is injected from the MOS transistor 2 to the floating gate 10 by a tunnel current, and electrons are injected from the ballistic electron source 3 to the floating gate 10. Thereby, electrons and holes are continuously recombined in the floating gate 10 to emit light, so that continuous oscillation operation is realized.

  O The MOS structure light emitting element 1 is in the form of a transistor made of MOS structure silicon, and in a process compatible with the silicon CMOS process, a MOS structure light emitting element can be fabricated with a silicon-based device. The light emitting element 1 and the integrated electronic circuit chip (silicon CMOS circuit) can be monolithically integrated. Therefore, it is possible to realize a light emitting element 1 having a MOS structure that can be continuously oscillated and can be monolithically integrated with a silicon CMOS circuit.

  ○ Since the floating gate 10 is formed of a material containing silicon nanoparticles, the electrons and holes are continuously recombined in the floating gate 10 so that the silicon nanoparticles in the floating gate 10 emit light continuously. .

  Since the MOS transistor 2 is a p-channel MOS transistor using holes as carriers, holes can be efficiently injected from the MOS transistor 2 to the floating gate 10 by a tunnel current, and the light emission efficiency is improved.

(Second Embodiment)
FIG. 2 is a schematic diagram showing a schematic configuration of a light emitting element 1 ′ having a MOS structure according to the second embodiment of the present invention. In the figure, in order to conceptually represent carrier injection, ● represents an electron, and ○ represents a hole.

  The light emitting element 1 ′ having a MOS structure includes a MOS transistor 2 and a ballistic electron source 3 ′ formed immediately below the gate electrode 7 of the MOS transistor 2. The MOS transistor 2 used in the present embodiment is a p-channel MOS (p-MOS) transistor.

  The MOS transistor 2 includes an n-type silicon substrate 5 including a channel region 4, a gate electrode 7 formed via a gate insulating film 6 corresponding to the channel region 4 on the silicon substrate 5, and a silicon substrate 5 P-type source region 8 and p-type drain region 9 formed on both sides of channel region 4.

  Further, the MOS transistor 2 is formed in the gate insulating film 6 between the ballistic electron source 3 ′ formed immediately below the gate electrode 7 and the channel region 4 of the silicon substrate 5, and electrons and holes are recombined. A floating gate 10 including silicon nanoparticles as a material capable of emitting light is formed.

  In the MOS transistor 2, the floating gate 10 is formed in the gate insulating film 6, and the gate insulating film 6 includes the first insulating film 6 a closer to the silicon substrate 5 than the floating gate 10 and the gate electrode 7 from the floating gate 10. The second insulating film 6b is divided into two parts. That is, the first insulating film 6a is formed on the silicon substrate 5, the floating gate 10 containing silicon nanoparticles is formed on the first insulating film 6a, and the second insulating film 6b is formed on the floating gate 10. Further, a ballistic electron source 3 'is formed on the second insulating film 6b, and a gate electrode 7 is continuously formed on the ballistic electron source 3'.

  Thus, in the light emitting element 1 ′ having the MOS structure according to the second embodiment, first, the MOS transistor (MOS circuit) 2 is formed on the surface of the silicon substrate 5. The first insulating film 6a above the channel region 4 is a silicon oxide film, and the thickness thereof is, for example, 3 nm to 10 nm, so that a tunnel current can flow. The gate length is, for example, 5 μm, and the size of 5 μm is a light emitting region.

  As the gate electrode 7, a polysilicon electrode is used. By anodizing the polysilicon electrode itself, the portion immediately below the gate electrode 7 is made porous to function as a ballistic electron source 3 '.

  The ballistic electron source 3 'and the floating gate 10 layer as the light emitting layer are separated by a very thin insulating film (second insulating film 6b) of several nm.

  The gate electrode 7 is connected to the ground, and a high voltage is applied between the source electrode (not shown) above the p-type source region 8 and the drain electrode (not shown) above the p-type drain region 9 and to the silicon substrate 5. Thus, holes are injected from the MOS transistor 2 into the floating gate 10 by a tunnel current, and at the same time, electrons are emitted from the ballistic electron source 3 ′ to the floating gate side. As a result, the electron-holes recombine and emit light in the floating gate 10 containing silicon nanoparticles.

  In the floating gate 10, both holes and electrons disappear due to recombination, but the above potential is maintained, that is, the gate electrode 7 is connected to the ground, and a high voltage is applied between the source electrode and the drain electrode and between the silicon substrate 5. By applying the voltage, electrons and holes are continuously supplied into the floating gate 10 to achieve continuous light emission.

  The silicon nanoparticles contained in the floating gate 10 can be manufactured, for example, by anodizing polycrystalline silicon with nanocrystalline silicon having a diameter of about 3 nm. It is said that the physical properties of photon emission of visible light that cannot be seen in the normal bulk crystalline silicon state appear when the diameter of the silicon particles becomes silicon nanoparticles with a Bohr radius of 4 nm or less.

  According to 2nd Embodiment which has the above structure, there exist the following effects.

  A hole is injected from the MOS transistor 2 to the floating gate 10 by a tunnel current, and electrons are injected from the ballistic electron source 3 ′ to the floating gate 10. Thereby, electrons and holes are continuously recombined in the floating gate 10 to emit light, so that continuous oscillation operation is realized.

  O The MOS structure light-emitting element 1 'is in the form of a transistor made of silicon with a MOS structure, and a MOS structure light-emitting element can be fabricated with a silicon-based device in a process compatible with the silicon CMOS process. The light emitting element 1 ′ and the integrated electronic circuit chip (silicon CMOS circuit) can be monolithically integrated. Therefore, it is possible to realize a light emitting element 1 ′ having a MOS structure capable of continuous oscillation operation and monolithically integrated with a silicon CMOS circuit.

  ○ Since the floating gate 10 is formed of a material containing silicon nanoparticles, the electrons and holes are continuously recombined in the floating gate 10 so that the silicon nanoparticles in the floating gate 10 emit light continuously. . Since the MOS transistor 2 is a p-channel MOS transistor using holes as carriers, holes can be efficiently injected from the MOS transistor 2 to the floating gate 10 by a tunnel current, and the light emission efficiency is improved.

(Third embodiment)
Next, a MOS structure light emitting device 1A according to a third embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a schematic diagram for explaining the light emission principle of the light emitting element 1A having the MOS structure. FIG. 4 is a plan view showing a schematic configuration of a light emitting element 1A having a MOS structure. In FIG. 3, the source region 81 of the right MOS transistor 21 and the drain region 92 of the left MOS transistor 22 are drawn next to each other, but this is for the purpose of understanding the operation and explaining it cheaply. Actually, in the two MOS transistors 21 and 22, as shown in FIG. 4, the source regions 81 and 82 and the drain regions 91 and 92 are adjacent to each other.

  As shown in FIGS. 3 and 4, the light emitting element 1A having the MOS structure is a second MOS transistor 21 which is a p-channel MOS (p-MOS) transistor and an n-channel MOS (n-MOS) transistor. And a first MOS transistor 22. The light emitting element 1A having the MOS structure has a structure including one floating gate 10A shared by the two MOS transistors 21 and 22. The floating gate 10A contains silicon nanoparticles as in the first embodiment.

  The second MOS transistor 21 is a p-channel MOS transistor having a structure similar to that of the MOS transistor 2 shown in FIG. 1, and an n-type silicon substrate 51 including a channel region 41 and a channel region 41 on the silicon substrate 51. Correspondingly, a gate electrode 71 formed through a gate insulating film (not shown) and a p-type source region 81 and a p-type drain region 91 formed on both sides of the channel region 41 on the silicon substrate 51 are provided. Prepare.

  Further, the gate insulating film (not shown) of the second MOS transistor 21 is a first insulating film (not shown) closer to the silicon substrate 51 than the floating gate 10A, like the gate insulating film 6 of the MOS transistor 2 shown in FIG. And a second insulating film (not shown) closer to the gate electrode 71 than the floating gate 10A. The first insulating film above the channel region 41 is a silicon oxide film, and has a thickness of, for example, 3 nm to 10 nm, so that a tunnel current can flow. The gate length is 5 μm, for example.

  The first MOS transistor 22 which is an n-channel MOS transistor includes a p-type silicon substrate 52 including a channel region 42 and a gate insulating film (not shown) corresponding to the channel region 42 on the silicon substrate 52. And an n-type source region 82 and an n-type drain region 92 formed on both sides of the channel region 42 on the silicon substrate 52.

  Further, the gate insulating film of the first MOS transistor 22 is floating with the first insulating film (not shown) closer to the silicon substrate 52 than the floating gate 10A, like the gate insulating film 6 of the MOS transistor 2 shown in FIG. The second insulating film (not shown) on the gate electrode 72 side from the gate 10A is divided into two parts. The first insulating film above the channel region 42 is a silicon oxide film, and the thickness thereof is, for example, 3 nm to 10 nm, so that a tunnel current can flow. The gate length is 5 μm, for example.

  The gate interval between the two MOS transistors 21 and 22 is, for example, 5 μm, the length of the floating gate 10A is 15 μm, and the width thereof is, for example, 5 μm. The middle part of the floating gate 10A emits light most. In addition, ITO transparent electrodes are used for the gate electrodes 71 and 72 of the two MOS transistors 21 and 22, respectively, to facilitate light extraction.

  As described above, the light emitting element 1A having the MOS structure includes the second MOS transistor 21 and the first MOS transistor 22, and one floating 10A containing a material capable of emitting light by recombination of electrons and holes. The floating gate 10A has its right end side (one end side) located in the gate insulating film between the gate electrode 71 of the second MOS transistor 21 and the channel region 41, and its left end side (the other end side). It is formed so as to be located in the gate insulating film between the gate electrode 72 of one MOS transistor 22 and the channel region 42.

  The light emitting element 1A having the MOS structure injects holes from the second MOS transistor 21 to the right end side of the floating gate 10A and injects electrons from the first MOS transistor 22 to the left end side of the floating gate 10A. Light is emitted near the middle of the floating gate 10A.

Next, the operation of the light emitting element 1A having the MOS structure configured as described above will be described.
The silicon substrate 52 side of the first MOS transistor 22 which is an n-channel MOS transistor is set to the ground (potential 1), and the gate electrode 72 side is set to the high potential (potential 2).

  In addition, the gate electrode 71 side potential (potential 3) of the second MOS transistor 21 which is a p-channel MOS transistor is higher than or equal to the gate electrode 71 side potential (potential 2) of the first MOS transistor 22. The potential of the second MOS transistor 21 on the silicon substrate 51 side (potential 4) is set to be higher than the potential on the gate electrode 71 side (potential 3).

That is, the potential applied to the silicon substrate 52 and the gate electrode 72 of the first MOS transistor 22 is the potential 1 and the potential 2, respectively, and the potential applied to the gate electrode 71 and the silicon substrate 51 of the second MOS transistor 21 is the potential. 3 and potential 4,
Potential 1 <potential 2 ≦ potential 3 <potential 4
To satisfy the relationship.

As a result, holes are injected from the second MOS transistor 21 to the right end side of the floating gate 10A by the tunnel current, and electrons are injected from the first MOS transistor 22 to the left end side of the floating gate 10A by the tunnel current. Due to the injected carriers, a spatial distribution of carriers (carrier distribution) occurs in the floating gate 10A. At the same time as the diffusion current flows so that this distribution is in an equilibrium state, the gate potential (potential 2, potential 3) and the substrate potential (potential 1, potential 4) satisfy the above relationship, thereby allowing the floating gate 10A. A potential difference is generated in the direction in which the carriers gather in the center on the left and right. Accordingly, in addition to the diffusion current, a drift current flows due to a potential difference in the direction in which carriers generated on the left and right of the floating gate 10A gather in the center, and electrons and holes move toward the center of the floating gate 10A. Near the middle of the gate 10A, electrons and holes are continuously recombined to emit light, and a continuous oscillation operation is realized.
According to 3rd Embodiment which has the above structure, there exist the following effects.

  O Floating gate 10A is shared by two MOS transistors 21 and 22, holes are injected from the first MOS transistor 21 to the floating gate 10A by a tunnel current, and tunneling from the second MOS transistor 22 to the floating gate 10A Electrons are injected by current. As a result, carrier distribution is generated in the floating gate 10A, so that a diffusion current flows and electrons and holes move toward the center of the floating gate 10A, and the electrons and holes continuously reappear near the middle in the floating gate 10A. Combined to emit light, a continuous oscillation operation is realized.

  Furthermore, by adopting the above-described method of applying the potential difference, that is, by satisfying the relationship of potential 1 <potential 2 ≦ potential 3 <potential 4, a drift current flows in addition to the diffusion current, and the center of the floating gate 10A The carrier moves efficiently to the part side, and electrons and holes continuously recombine near the middle in the floating gate 10A to emit light, thereby realizing an efficient continuous oscillation operation.

  The light emitting element 1A having a MOS structure includes a first MOS transistor 21 that is a p-channel MOS transistor and a second MOS transistor 22 that is an n-channel MOS transistor. For this reason, holes can be efficiently injected from the first MOS transistor 21 to the right end side of the floating gate 10A and electrons can be efficiently injected from the second MOS transistor 22 to the left end side of the floating gate 10A by the tunnel current. Will improve.

  The light emitting element 1A having a MOS structure can be configured by a single CMOS transistor including a first MOS transistor 21 that is a p-channel MOS transistor and a second MOS transistor 22 that is an n-channel MOS transistor. This facilitates monolithic integration with the CMOS circuit.

(Fourth embodiment)
Next, a MOS structure light emitting device according to a fourth embodiment of the present invention will be described.
This MOS structure light emitting element is the same as that of the MOS structure light emitting element 1 according to the first embodiment shown in FIG. 1 except that silicon nanoparticles are used as a material of the floating gate 10 (a material capable of emitting light by recombination of electrons and holes). Instead, a direct transition type semiconductor material is used. Specifically, AlGaN was used as the semiconductor material. The gate insulating film 6 (insulating films 6a and 6b) above the channel region 4 (see FIG. 1) is not a silicon oxide film but an epitaxially grown Al ₂ O ₃ single crystal film. Other configurations are the same as those of the light-emitting element 1 having the MOS structure according to the first embodiment.

  According to 4th Embodiment which has the above structure, in addition to the effect which the said 1st Embodiment show | plays, there exist the following effects.

  O Light is emitted continuously in the floating gate by recombination of electrons and holes continuously in the floating gate formed of a direct transition type semiconductor material.

  ○ Luminous efficiency is improved by using a direct transition type semiconductor material as a floating gate material.

  The gate insulating film is formed in two parts: a first insulating film 6a closer to the silicon substrate 5 than the floating gate 10 and a second insulating film 6b closer to the gate electrode 7 than the floating gate 10 (see FIG. 1). . Since the floating gate 10 is formed by directly growing the transition type semiconductor on the first insulating film 6a, the process is easier than growing the transition type semiconductor directly on the silicon substrate, and an insulating film material is used. By selecting, various direct transition type semiconductor materials can be handled.

  O Since a PN junction is not required for the light emitting material itself, the process is easier than a method of manufacturing a light emitting element using a transition semiconductor material directly on a silicon substrate.

(Fifth embodiment)
Next, a MOS structure light emitting device according to a fifth embodiment of the invention will be described.

This MOS structure light emitting element is made of silicon as a material for the floating gate 10A (a material capable of emitting light by recombination of electrons and holes) in the MOS structure light emitting element 1A according to the third embodiment shown in FIGS. Instead of nanoparticles, direct transition type semiconductor materials are used. Specifically, AlGaN was used as the semiconductor material. The gate insulating film above the channel regions 41 and 42 (see FIG. 3) of the two MOS transistors 21 and 22 is not a silicon oxide film but an epitaxially grown Al ₂ O ₃ single crystal film. Other configurations are the same as those of the light emitting element 1A having the MOS structure according to the third embodiment.

  According to 5th Embodiment which has the above structure, in addition to the effect which the said 3rd Embodiment show | plays, there exist the following effects.

  O Light is continuously emitted in the floating gate 10A by recombining electrons and holes continuously in the vicinity of the middle in the floating gate 10A (see FIG. 3) formed of a direct transition type semiconductor material.

  ○ Luminous efficiency is improved by using a direct transition type semiconductor material as a floating gate material.

  The gate insulating film (the first insulating film 6a of the gate insulating film 6 shown in FIG. 1) above the channel regions 41 and 42 (see FIG. 3) of the two MOS transistors 21 and 22 is a floating gate. The first insulating film 6a on the silicon substrate 5 side from 10A and the second insulating film 6b on the gate electrode 7 side from the floating gate 10 are formed separately (see FIG. 1). Since the floating gate 10 is formed by directly growing the transition type semiconductor on the first insulating film 6a, the process is easier than growing the transition type semiconductor directly on the silicon substrate, and an insulating film material is used. By selecting, various direct transition type semiconductor materials can be handled.

  O Since a PN junction is not required for the light emitting material itself, the process is easier than a method of manufacturing a light emitting element using a transition semiconductor material directly on a silicon substrate.

  In addition, this invention can also be changed and embodied as follows.

  In the first to third embodiments, the floating gate 10 is formed of a material containing silicon nanoparticles as an example of “a material capable of emitting light by recombination of electrons and holes”. In the fourth and fifth embodiments, AlGaN, which is a direct transition semiconductor material, is used as “a material that can emit light by recombination of electrons and holes”. The present invention is not limited to the MOS structure light emitting device having such a configuration. The present invention is also applicable to a MOS light emitting device having a structure using silicon nanoparticles or “material capable of emitting light by recombination of electrons and holes” other than silicon nanoparticles or a direct transition semiconductor material as a material of the floating gates 10 and 10A. Is done.

  The present invention can also be applied to a light emitting element having a MOS structure using a nitride semiconductor material such as GaN or InGaN as a direct transition type semiconductor material used for the floating gates 10 and 10A. is there.

  In each of the above embodiments, the MOS structure light emitting device having a structure using an i-type semiconductor (intrinsic semiconductor) that is not doped with impurities as a material containing silicon nanoparticles forming a floating gate or a direct transition semiconductor material. The present invention is applicable.

  In a general light emitting element using a PN junction, impurity doping is performed in order to manufacture a p-type semiconductor and an n-type semiconductor, so that carrier mobility is lowered and high-speed operation is hindered. On the other hand, by using an i-type semiconductor not doped with impurities as a semiconductor used for the floating gate, carrier mobility can be increased, and high-speed operation performance as a light source is improved.

  In the third embodiment, two types of MOS transistors, that is, the second MOS transistor 21 that is a p-channel MOS transistor and the first MOS transistor 22 that is an n-channel MOS transistor are used. This is because both types of transistors are manufactured in a CMOS circuit, so that monolithic integration with the CMOS circuit is easy. For the purpose of light emission, two p-channel MOS transistors are used. The MOS structure light emitting element 1A may be configured, or the MOS structure light emitting element 1A may be configured by using two n-channel MOS transistors.

1 is a schematic diagram showing a schematic configuration of a light emitting element having a MOS structure according to a first embodiment. FIG. The top view which shows schematic structure of the light emitting element of the MOS structure which concerns on 2nd Embodiment. The schematic diagram for demonstrating the light emission principle of the light emitting element of the MOS structure which concerns on 3rd Embodiment. The top view which shows schematic structure of the light emitting element of the MOS structure which concerns on 3rd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,1 ', 1A ... Light emitting element of MOS structure, 2,21 ... p channel type MOS transistor, 22 ... n channel type MOS transistor, 3,3' ... ballistic electron source, 4,41.42 ... channel region, 5 , 51, 52 ... silicon substrate, 6 ... gate insulating film, 6a ... first insulating film, 6b ... second insulating film, 7, 71, 72 ... gate electrode, 8, 81 ... p-type source region, 9, 91 ... p-type drain region, 82 ... n-type source region, 92 ... n-type drain region, 10, 10A ... floating gate.

Claims (10)

MOS transistor,
A floating gate formed in a gate insulating film between the gate electrode and the channel region of the MOS transistor, and containing a material capable of emitting light by recombination of electrons and holes;
A ballistic electron source disposed directly below the MOS transistor,
A light emitting element having a MOS structure, wherein holes are injected into the floating gate from the MOS transistor, and electrons are injected into the floating gate from the ballistic electron source, whereby light is emitted in the floating gate. MOS transistor,
A ballistic electron source disposed directly under the gate electrode of the MOS transistor;
A floating gate formed in a gate insulating film between a ballistic electron source and a channel region directly below the gate electrode of the MOS transistor, and containing a material capable of emitting light by recombination of electrons and holes,
A light emitting element having a MOS structure, wherein holes are injected into the floating gate from the MOS transistor, and electrons are injected into the floating gate from the ballistic electron source, whereby light is emitted in the floating gate. A first MOS transistor and a second MOS transistor;
One end side is located in the gate insulating film between the gate electrode and the channel region of the first MOS transistor, and the other end side is located in the gate insulating film between the gate electrode and the channel region of the second MOS transistor. A floating gate including a material formed to be located and capable of emitting light by recombination of electrons and holes;
A light emitting device having a MOS structure, wherein electrons are emitted from the first MOS transistor to the floating gate and holes are injected from the second MOS transistor to the floating gate to emit light in the floating gate. .   4. The MOS structure light emitting device according to claim 3, wherein the first MOS transistor is an n-channel type MOS transistor, and the second MOS transistor is a p-channel type MOS transistor. If the potential applied to the substrate and gate electrode of the first MOS transistor is potential 1 and potential 2, respectively, and the potential applied to the gate electrode and substrate of the second MOS transistor is potential 3 and potential 4, respectively.
Potential 1 <potential 2 ≦ potential 3 <potential 4
The light emitting device of the MOS structure according to claim 4, wherein:   The MOS transistor includes a silicon substrate including a channel region, a gate electrode formed via a gate insulating film corresponding to the channel region on the substrate, and on both sides of the channel region on the silicon substrate. 6. The MOS light emitting device according to claim 1, further comprising a source region and a drain region formed.   7. The MOS structure light emitting device according to claim 1, wherein the floating gate is made of a material containing silicon nanoparticles.   7. The light emitting device having a MOS structure according to claim 1, wherein the floating gate is made of a direct transition type semiconductor material.   9. The MOS structure light-emitting device according to claim 7, wherein an i-type semiconductor not doped with impurities is used as the material containing the silicon nanoparticles forming the floating gate or the direct transition semiconductor material. .   3. The MOS structure light emitting device according to claim 1, wherein the MOS transistor is a p-channel MOS transistor.

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