JP4916859B2 - SEMICONDUCTOR DEVICE, DISPLAY DEVICE, ELECTRONIC DEVICE, AND SEMICONDUCTOR DEVICE MANUFACTURING METHOD - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device having a light-emitting element of excellent light-emitting performance. <P>SOLUTION: The semiconductor device comprises a first concave or an opening 16a formed in an insulating film 16; a first electrode 17 which is positioned on a portion surrounding the first concave or the opening 16a of the insulating film 16 and in the first concave or the opening 16a, and forms a second concave 17a together with the first concave or the opening 16a; a semiconductor layer 18 of a first conductivity type which is formed on the first electrode 17, and forms a third concave 18a together with the second concave 17a; a light-emitting layer 19 which is formed on the semiconductor layer 18 of the first conductivity type, and forms a fourth concave 19a together with the third concave 18a; a semiconductor layer 20 of a second conductivity type which is formed on the light-emitting layer 19, and forms a fifth concave 20a together with the fourth concave 19a; and a second electrode 21 which is formed on the semiconductor layer 20 of the second conductivity type, and constitutes the bottom face and the side face of the fifth concave 20a. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to a semiconductor device, a display device, an electronic device, and a method for manufacturing a semiconductor device having a light emitting element with excellent light emission characteristics.

  FIG. 16 is a diagram for explaining the structure of a conventional light emitting device. A conventional light emitting element has a structure in which a lower electrode 1002, a first conductive semiconductor layer 1004, a light emitting layer 1006, a second conductive semiconductor layer 1008, and an upper electrode 1010 are stacked in this order on an insulating film 1000. When a predetermined potential is applied to each of the lower electrode 1002 and the upper electrode 1010, excitons are recombined in the light emitting layer 1006, and energy released at the time of recombination is emitted as light.

In the case of forming a display using a light emitting element, it is necessary to emit light from the upper surface of the light emitting element. When the upper electrode 1010 is formed of metal, there is a method of emitting light from the upper surface by setting the film thickness of the upper electrode 1010 to 5 to 200 nm. According to this method, when the thickness of the upper electrode 1010 made of Ni is set to 15 nm, the transmittance of ultraviolet light emitted from the light emitting element becomes 70% or more (for example, Patent Document 1).
JP 2004-221132 A (paragraphs 43 and 57)

  According to the above-described conventional technology, the transmittance of emitted light becomes 70% or more by reducing the thickness of the upper electrode (for example, 15 nm). However, when the light emitting element is used as a display, the light transmittance of the upper electrode is desired to be 80% or more.

  In addition, there is a method of using a transparent electrode such as ITO or ZnO as the upper electrode. However, since the transparent electrode has high resistance, power is consumed by the transparent electrode, and the light emission efficiency of the light emitting element is lowered. In addition, in the case where ultraviolet light is emitted using ZnO as the light emitting layer, if ZnO is used as the upper electrode, the emitted ultraviolet light is absorbed by the upper electrode.

  The present invention has been made in consideration of the above-described circumstances, and an object of the present invention is to provide a semiconductor device, a display device, an electronic device, and a method for manufacturing the semiconductor device having a light emitting element with excellent light emission efficiency on the upper surface. It is to provide.

  In order to solve the above problems, a semiconductor device according to the present invention includes a first recess or opening formed in an insulating film, an insulating film positioned around the first recess or opening, and a first A first electrode formed on the bottom and side surfaces of the recess or opening and having a second recess located in the first recess or in the opening, and formed on the first electrode and in the second recess A first conductive type semiconductor layer having a third concave portion located; a light emitting layer formed on the first conductive type semiconductor layer and having a fourth concave portion located in the third concave portion; and Formed on the second conductive type semiconductor layer having the fifth concave portion located in the fourth concave portion and the second conductive type semiconductor layer constituting the bottom surface and the side surface of the fifth concave portion. And a second electrode.

  According to this semiconductor device, the first electrode, the first conductivity type semiconductor layer, the light emitting layer, and the second conductivity type semiconductor layer are formed on the bottom surface and side surfaces of the first recess or opening formed in the insulating film. It is formed along. For this reason, the light emitted from the light emitting layer is emitted from the upper surface of the light emitting element after passing through the semiconductor layer of the second conductivity type. Therefore, the light emitted from the light emitting layer is efficiently emitted from the upper surface of the light emitting element.

  When the band gap of the second conductivity type semiconductor layer is less than or equal to the band gap of the light emitting layer, the thickness of the second conductivity type semiconductor layer is preferably thinner than the thickness of the light emitting layer. In this way, it is possible to suppress the light emitted from the light emitting layer from being absorbed by the second conductivity type semiconductor layer.

  Another semiconductor device according to the present invention is formed on the first recess or opening formed in the insulating film, and on the bottom surface and the side surface of the first recess or opening, and is located in the first recess or opening. A first electrode having a second recess, a first conductivity type semiconductor layer formed on the first electrode and having a third recess located in the second recess, and a first conductivity type semiconductor A light emitting layer having a fourth recess formed on the layer and located in the third recess, and a second conductivity type having a fifth recess formed on the light emitting layer and located in the fourth recess. A semiconductor layer and a second electrode formed on the second conductivity type semiconductor layer constituting the bottom and side surfaces of the fifth recess, and the angle of the end face of the light emitting layer with respect to the surface of the insulating film is 90 ° It is less than 270 °.

  According to this semiconductor device, since the angle of the end face of the light emitting layer with respect to the surface of the insulating film is more than 90 ° and less than 270 °, light emitted from the light emitting layer is emitted upward from the end face of the light emitting layer. Therefore, the light emitted from the light emitting layer is efficiently emitted from the upper surface of the light emitting element.

The light emitting layer may be made of a material having a band gap of 3 eV or more. In this case, the material constituting the light emitting layer is ZnO, ZnS, GaN, SiC, or _{Mg 1-X} Zn X O.

Each of the material constituting the first conductivity type semiconductor layer and the material constituting the second conductivity type semiconductor layer preferably has a larger band gap than the material constituting the light emitting layer. In this case, the luminous efficiency of the light emitting layer is increased. Further, when the thickness of the light emitting layer is 10 nm or less, a quantum well structure is formed, and thus the light emission efficiency of the light emitting layer is further increased. Note that when the material forming the light emitting layer is ZnO, the material forming the first conductive type semiconductor layer and the material forming the second conductive type semiconductor layer are Mg _1-X Zn into which impurities are introduced. _X O can be used.

  The first electrode preferably has a reflectance of 90% or higher for light emitted from the light emitting layer. In this case, the light emitted downward from the light emitting layer is reflected by the first electrode and emitted from the upper surface of the light emitting element. Therefore, the light emitted from the light emitting layer is more efficiently emitted from the upper surface of the light emitting element.

  Another semiconductor device according to the present invention includes a thin film transistor formed on a substrate, an insulating film positioned above or above the thin film transistor, and a light emitting element formed on the insulating film and whose light emission is controlled by the thin film transistor. The light emitting element includes a first recess or opening formed in the insulating film, an insulating film positioned around the first recess or opening, and a bottom surface and a side surface of the first recess or opening. A first electrode having a second recess formed in the first recess or in the opening, and a third electrode formed on the first electrode and having a third recess positioned in the second recess. A first-conductivity-type semiconductor layer; a light-emitting layer formed on the first-conductivity-type semiconductor layer and having a fourth recess located in the third recess; and a light-emitting layer formed on the light-emitting layer and in the fourth recess Second-conductivity-type semiconductor layer having a fifth recess located in , And a second electrode formed on the second conductive type semiconductor layer constituting the bottom and side surfaces of the fifth recess.

  Another semiconductor device according to the present invention includes a thin film transistor formed on a substrate, an insulating film positioned above or above the thin film transistor, and a light emitting element formed on the insulating film and whose light emission is controlled by the thin film transistor. The light emitting element is formed on the first electrode and the first electrode which is formed on the bottom surface and the side surface of the first recess or the opening and has the second recess positioned in the first recess or the opening. A first conductive type semiconductor layer having a third concave portion located in the second concave portion, and a fourth concave portion formed on the first conductive type semiconductor layer and located in the third concave portion. A light emitting layer having a second conductive type formed on the light emitting layer and having a fifth concave portion located in the fourth concave portion, and a second conductive type constituting a bottom surface and a side surface of the fifth concave portion And a second electrode formed on the semiconductor layer. Angle of the end face of the light-emitting layer to the surface of the film is less than 90 ° super 270 °.

  The thin film transistor may include an island-shaped ZnO film and an impurity region formed in the ZnO film and serving as a source or a drain of the thin film transistor. In this case, the semiconductor layer of the thin film transistor can be formed by a sputtering method. Therefore, a flexible substrate or a plastic substrate can be used as the substrate.

  A display device according to the present invention includes a thin film transistor formed on a substrate, an insulating film positioned above or above the thin film transistor, a light emitting element that is formed on the insulating film and emits ultraviolet light, and the light emission is controlled by the thin film transistor. And a phosphor that is located above or above the light-emitting element and absorbs ultraviolet light emitted from the light-emitting element and emits visible light. The light-emitting element has a first recess formed in the insulating film. Alternatively, the opening is formed on the insulating film positioned around the first recess or the opening, and on the bottom surface and the side surface of the first recess or the opening, and the second positioned in the first recess or the opening. A first electrode having a plurality of recesses, a first conductivity type semiconductor layer formed on the first electrode and having a third recess located in the second recess, and on the first conductivity type semiconductor layer And a fourth recess located in the third recess. A light emitting layer having a second conductivity type semiconductor layer formed on the light emitting layer and having a fifth recess located in the fourth recess, and a second conductivity constituting a bottom surface and a side surface of the fifth recess. And a second electrode formed on the semiconductor layer of the mold.

  Another display device according to the present invention includes a thin film transistor formed over a substrate, an insulating film positioned on or above the thin film transistor, and formed on the insulating film, emits ultraviolet light, and light emission is controlled by the thin film transistor. A light-emitting element; and a phosphor that is positioned above or above the light-emitting element and that absorbs ultraviolet light emitted from the light-emitting element and emits visible light. The light-emitting element is formed in an insulating film. A first electrode having a second recess formed on a bottom surface and a side surface of the first recess or opening, and having a second recess positioned in the first recess or opening; and on the first electrode A first conductive type semiconductor layer having a third concave portion formed and located in the second concave portion, and a fourth concave portion formed on the first conductive type semiconductor layer and located in the third concave portion A light emitting layer, and a fourth recess formed on the light emitting layer A second conductivity type semiconductor layer having a fifth recess located in the second recess, and a second electrode formed on the second conductivity type semiconductor layer constituting the bottom and side surfaces of the fifth recess, The angle of the end face of the light emitting layer with respect to the surface of the insulating film is more than 90 ° and less than 270 °.

  The thin film transistor may include an island-shaped ZnO film and an impurity region formed in the ZnO film and serving as a source or a drain of the thin film transistor. In this case, a flexible substrate or a plastic substrate can be used as the substrate.

  An electronic apparatus according to the present invention includes any of the semiconductor devices or display devices described above.

  In the method for manufacturing a semiconductor device according to the present invention, a first recess or opening is formed in an insulating film, and a first conductive film is formed on the insulating film and on the bottom and side surfaces of the first recess or opening. By forming a second recess located in the first recess or in the opening, and forming a first conductivity type semiconductor layer on the first conductive film, the second recess located in the second recess is formed. 3 is formed, and a light emitting layer is formed on the first conductivity type semiconductor layer to form a fourth recess located in the third recess, and the second conductivity type semiconductor is formed on the light emitting layer. Forming a fifth recess located in the fourth recess, forming a second conductive film on the second conductivity type semiconductor layer, forming the first and second conductive films; Of the first conductivity type semiconductor layer, the second conductivity type semiconductor layer, and the light emitting layer, a portion located on the insulating film is selectively etched. It is intended to remove the ring.

  In another method of manufacturing a semiconductor device according to the present invention, a first recess or opening is formed in an insulating film, and a first conductive film is formed on the insulating film and on the bottom and side surfaces of the first recess or opening. By forming a second recess located in the first recess or in the opening, and forming a first conductivity type semiconductor layer on the first conductive film, the second recess is positioned in the second recess. Forming a third recess and forming a light emitting layer on the first conductivity type semiconductor layer, thereby forming a fourth recess located in the third recess, and forming a second conductivity type on the light emitting layer. By forming the first semiconductor layer, the fifth concave portion located in the fourth concave portion is formed, the second conductive film is formed on the second conductive type semiconductor layer, and the first and second conductive layers are formed. Of the film, the first conductive type semiconductor layer, the second conductive type semiconductor layer, and the light emitting layer, a portion located on the insulating film is polished or It is intended to be removed by Tchibakku.

  In another method of manufacturing a semiconductor device according to the present invention, a thin film transistor is formed on a substrate, an insulating film is formed on the thin film transistor, a first concave portion located above the thin film transistor is formed in the insulating film, A connection hole located on the source or drain of the thin film transistor is formed in the bottom surface of the recess of the first recess, and the connection hole is electrically connected to the source or drain through the connection hole on the insulating film and on the bottom surface and side surface of the first recess. By forming the first conductive film, the second concave portion located in the first concave portion is formed, and by forming the first conductive type semiconductor layer on the first conductive film, the second concave portion is formed. Forming a third recess located in the first recess and forming a light emitting layer on the first conductivity type semiconductor layer, thereby forming a fourth recess positioned in the third recess; By forming a two-conductivity type semiconductor layer A fifth recess located in the fourth recess is formed, a second conductive film is formed on the second conductivity type semiconductor layer, and the first and second conductive films and the first conductivity type semiconductor layer are formed. Of the second conductivity type semiconductor layer and the light emitting layer, the portion located on the insulating film is removed by selective etching.

  In another method of manufacturing a semiconductor device according to the present invention, a thin film transistor is formed on a substrate, an insulating film is formed on the thin film transistor, a first concave portion located above the thin film transistor is formed in the insulating film, A connection hole located on the source or drain of the thin film transistor is formed in the bottom surface of the recess of the first recess, and the connection hole is electrically connected to the source or drain through the connection hole on the insulating film and on the bottom surface and side surface of the first recess. By forming the first conductive film, the second concave portion located in the first concave portion is formed, and by forming the first conductive type semiconductor layer on the first conductive film, the second concave portion is formed. Forming a third recess located in the first recess and forming a light emitting layer on the first conductivity type semiconductor layer, thereby forming a fourth recess positioned in the third recess; By forming a two-conductivity type semiconductor layer A fifth recess located in the fourth recess is formed, a second conductive film is formed on the second conductivity type semiconductor layer, and the first and second conductive films and the first conductivity type semiconductor layer are formed. Of the second conductivity type semiconductor layer and the light emitting layer, a portion located on the insulating film is removed by polishing or etch back.

  As described above, according to the present invention, the light emitted from the light emitting layer can be efficiently emitted from the upper surface of the light emitting element. Further, the intensity per unit area of light emitted to the upper surface can be increased. Further, it is possible to form a display device in which ultraviolet light emitted from the light emitting element is absorbed by a fluorescent film or the like and the fluorescent film emits R, G, and B. For this reason, the luminous efficiency of the display device can be increased. In addition, the lifetime of the display device can be extended as compared with the case where organic EL is used.

(First embodiment)
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1A is a cross-sectional view for explaining the structure of a light-emitting element according to the first embodiment of the present invention, and FIG. 1B is a plan view of the light-emitting element. Note that FIG. 1A shows a cross section taken along the line AA ′ of FIG. In this light emitting element, an insulating film 16 is formed on the substrate 10. The substrate 10 is a glass substrate, for example. The insulating film 16 is, for example, a silicon oxide film, and has a thickness of, for example, not less than 0.5 μm and not more than 1.5 μm. An opening 16 a is formed in the insulating film 16. The bottom surface of the opening 16a is, for example, a square having a side of 2.5 μm.

  A lower electrode 17 is formed on the insulating film 16 located around the opening 16a and on the bottom and side surfaces of the opening 16a. The lower electrode 17 forms a first recess 17a together with the opening 16a. Such a configuration can be realized by adjusting the film thickness of the lower electrode 17 with respect to the shape of the opening 16a. The film thickness of the lower electrode 17 is, for example, not less than 100 nm and not more than 300 nm (for example, 200 nm). The lower electrode 17 is preferably made of a material having a sufficiently high reflectance (for example, 90% or more) with respect to the light emitted from the light emitting layer 19. When the light emitting layer 19 emits ultraviolet light, the lower electrode 17 is made of, for example, Al.

  On the lower electrode 17, a p-type semiconductor layer 18, a light emitting layer 19, and an n-type semiconductor layer 20 are stacked in this order. The p-type semiconductor layer 18 has a second recess 18a positioned inside the first recess 17a, and the light emitting layer 19 has a third recess 19a positioned inside the second recess 18a. The n-type semiconductor layer 20 has a fourth recess 20a located inside the third recess 19a. Such a configuration can be realized by adjusting the film thicknesses of the p-type semiconductor layer 18, the light emitting layer 19, and the n-type semiconductor layer 20. The thickness of the p-type semiconductor layer 18 is, for example, 100 nm to 500 nm (for example, 200 nm), the thickness of the light emitting layer 19 is, for example, 500 nm to 10,000 nm (for example, 500 nm), and the thickness of the n-type semiconductor layer 20 is, for example, 100 nm or more and 500 nm or less (for example, 200 nm). However, the film thickness of the n-type semiconductor layer 20 is preferably thinner than the film thickness of the light emitting layer 19, and particularly preferably 1/2 or less. In this way, as will be described later, the light from the light emitting layer 19 is suppressed from being absorbed by the n-type semiconductor layer 20. For example, the band gap of the n-type semiconductor layer 20 is less than or equal to the band gap of the light emitting layer 19. However, light is efficiently emitted from the upper surface of the light emitting element.

The p-type semiconductor layer 18, the light emitting layer 19, and the n-type semiconductor layer 20 are, for example, a p-type ZnO layer, a ZnO layer into which impurities are not introduced (band gap is 3.4 eV), and an n-type ZnO layer. The p-type ZnO is, for example, ZnO into which phosphorus is introduced, and the n-type ZnO layer is, for example, ZnO into which Al or Ga is introduced. The light emitting layer 19 is a ZnS layer (with a band gap of 3.68 eV), a GaN layer (3.36 eV), an SiC layer (3.0 eV), or Mg _1-X Zn _X O (MgO and ZnO mixed crystal semiconductor). : Band gap of 3.4 eV or more and 7.8 eV or less) can also be used. When the band gap of the light emitting layer 19 is 3 eV or more, ultraviolet light can be emitted. When the light emitting layer 19 is GaAs (band gap is 1.42 eV), the p-type semiconductor layer 18 is Al _1-X Ga _X As (a band gap of 1.42 eV or more), which is a mixed crystal of GaAs and AlAs. 17eV or less) can be used are those formed by introducing a Zn, as the n-type semiconductor layer 20 can be used those obtained by introducing Si into _Al 1-X _Ga X as. In this structure, infrared light is emitted.

If the p-type semiconductor layer 18 and the n-type semiconductor layer 20 are made of a material having a band gap larger than that of the light emitting layer 19, the light emission efficiency of the light emitting layer 19 can be increased. In this case, since the quantum well structure can be obtained by reducing the thickness of the light emitting layer 19 (for example, 10 nm or less), the light emission efficiency can be particularly increased. When the light emitting layer 19 is formed of ZnO, Mg _{1 -X} Zn _X O into which Al or Ga is introduced is used as the p-type semiconductor layer 18 and Mg ₁ into which phosphorus is introduced as the n-type semiconductor layer 20. _{When -X} Zn _X O is used, the band gap of the p-type semiconductor layer 18 and the n-type semiconductor layer 20 can be made higher than that of the light emitting layer 19.

  On the lower electrode 17, the n-type semiconductor layer 20, the light emitting layer 19, and the p-type semiconductor layer 18 may be stacked in this order. In this case, the thickness of the p-type semiconductor layer 18 is preferably smaller than the thickness of the light emitting layer 19 (100 nm or more and 500 nm or less), and particularly preferably 1/2 or less.

  An upper electrode 21 is formed on the n-type semiconductor layer 20 located in and around the fourth recess 20a. The upper electrode 21 is made of a metal such as Al and is in contact with the entire surface of the n-type semiconductor layer 20 constituting the side surface and the bottom surface of the fourth recess 20a. However, when viewed from the direction perpendicular to the substrate 10, the upper electrode 21 needs not to overlap a portion of the light emitting layer 19 that extends in a direction substantially perpendicular to the substrate 10. That is, when viewed from a direction perpendicular to the substrate 10, the upper electrode 21 is formed such that the end portion of the upper electrode 21 formed by patterning is located inside the third recess 19a. In this way, as will be described later, the light emitted from the light emitting layer 19 is efficiently emitted from the upper surface of the light emitting element.

  When the light-emitting element shown in the drawing emits light, for example, the upper electrode 21 is grounded and a positive potential is applied to the lower electrode 17. Thereby, excitons are recombined in the light emitting layer 19, and energy released at the time of coupling is emitted as light. Since the upper electrode 21 does not overlap the portion of the light emitting layer 19 that extends upward in the figure, the light emitted upward in the figure passes through the n-type semiconductor layer 20 and then passes through the upper surface of the light emitting element. It is injected. Further, light emitted downward in the figure is reflected by the lower electrode 17 and is emitted from the upper surface of the light emitting element. In addition, since the film thickness of the n-type semiconductor layer 20 is thinner than the film thickness of the light-emitting layer 19 as described above, the light from the light-emitting layer 19 is suppressed from being absorbed by the n-type semiconductor layer 20, and light is efficiently emitted. Inject on top.

  In addition, the area | region which light-emits among the light emitting layers 19 is an area | region pinched | interposed between the lower electrode 17 and the upper electrode 21, ie, the part which forms the 3rd recessed part 19a. For this reason, since the area | region which light-emits can be earned in the direction perpendicular | vertical with respect to the board | substrate 10, the intensity | strength per unit area of the light inject | emitted on an upper surface becomes strong.

  Next, a method for manufacturing the light-emitting element shown in FIGS. 1A and 1B will be described. First, the insulating film 16 is formed on the substrate 10 by the CVD method. Next, a resist pattern is formed on the insulating film 16, and the insulating film 16 is selectively etched using the resist pattern as a mask. As a result, an opening 16 a is formed in the insulating film 16. Thereafter, the resist pattern is removed.

  Next, the lower electrode 17 is formed by sputtering on the entire surface of the insulating film 16 and on the bottom and side surfaces of the opening 16a. For example, an Al target is used as the target. Next, a p-type semiconductor layer 18 is formed on the lower electrode 17 by a sputtering method. As the target, for example, a ZnO target containing phosphorus is used.

  Next, a light emitting layer 19 is formed on the entire surface of the p-type semiconductor layer 18 by sputtering. For example, a ZnO target is used as the target, and a nitrogen atmosphere is used as the atmosphere. Next, an n-type semiconductor layer 20 is formed on the entire surface of the light emitting layer 19 by a sputtering method. As the target, for example, a ZnO target containing Ga or Al is used. Next, the upper electrode 21 is formed on the entire surface of the n-type semiconductor layer 20 by sputtering. For example, an Al target is used as the target.

  The p-type semiconductor layer 18 may be formed by introducing impurities such as phosphorus after forming the semiconductor layer by sputtering. The n-type semiconductor layer 20 is formed by placing a chip (for example, an Al piece or a Ga piece) made of impurities to be introduced on a target made of a semiconductor (for example, a ZnO target). May be a method of sputtering simultaneously.

  Next, a resist pattern is formed on the upper electrode 21, and the upper electrode 21 is selectively etched using the resist pattern as a mask. As a result, the upper electrode 21 is removed except for portions located in and around the fourth recess 20a. Thereafter, the resist pattern is removed.

  Next, a resist pattern is formed on the upper electrode 21 and the n-type semiconductor layer 20, and the n-type semiconductor layer 20, the light emitting layer 19, the p-type semiconductor layer 18, and the lower electrode 17 are selectively selected using the resist pattern as a mask. Etch. Thereby, the n-type semiconductor layer 20, the light emitting layer 19, the p-type semiconductor layer 18, and the lower electrode 17 are removed except for portions located in and around the opening 16a. Thereafter, the resist pattern is removed.

  As described above, according to the first embodiment of the present invention, the lower electrode 17, the p-type semiconductor layer 18, the light-emitting layer 19, and the n-type semiconductor layer 20 constituting the light-emitting element are formed on the insulating film 16. It is formed along the bottom and side surfaces of the opening 16a. The upper electrode 21 is formed in and around the fourth recess 20a, but does not overlap the portion of the light emitting layer 19 that extends upward in the drawing. For this reason, the light emitted from the light emitting layer 19 is emitted from the upper surface of the light emitting element after passing through the n-type semiconductor layer 20.

  Therefore, the light emitted from the light emitting layer 19 is efficiently emitted from the upper surface of the light emitting element. Further, since the lower electrode 17 is made of a material that reflects light emitted from the light emitting layer 19, the light emitted from the light emitting layer 19 is emitted from the upper surface of the light emitting element more efficiently.

  In addition, a region of the light emitting layer 19 that emits light can be earned in a direction perpendicular to the substrate 10. Therefore, the intensity per unit area of light emitted to the upper surface can be increased.

  Moreover, the substance which can form the p-type semiconductor layer 18, the light emitting layer 19, and the n-type semiconductor layer 20 by sputtering, such as a p-type ZnO layer, a ZnO layer into which no impurity is introduced, and an n-type ZnO layer, respectively. In this case, since these film formation temperatures can be lowered, a substrate having a lower heat resistant temperature than the glass substrate, such as a flexible substrate or a plastic substrate, can be used as the substrate 10.

  If the refractive index of the light emitting layer 19 is higher than the refractive index of the p-type semiconductor layer 18 and the refractive index of the n-type semiconductor layer 20, the light emitting layer 19 can be laser-oscillated. In this case, a semiconductor laser oscillation element with high luminous efficiency can be obtained.

(Second Embodiment)
FIG. 2 is a circuit diagram for explaining a configuration of a drive circuit for a light emitting element according to the second embodiment of the present invention. In the present embodiment, the light emitting element 904 has the same configuration as that of the light emitting element described in the first embodiment, and the counter electrode 908 corresponds to the upper electrode 21 in FIGS. . An electrode corresponding to the lower electrode 17 is electrically connected to a power supply line 907 via a driving TFT (thin film transistor) 901. The gate electrode of the driving TFT 901 is electrically connected to the signal line 906 through the switching TFT 902. A gate electrode of the switching TFT 902 is electrically connected to the scanning line 905. Note that the gate electrode of the driving TFT 901 is also connected to the power supply line 907 through the capacitor 903.

  In such a circuit, when a predetermined signal is input to the scanning line 905, the switching TFT 902 is turned on, and the signal line 906 and the gate electrode of the driving TFT 901 are connected. In this state, when a predetermined signal is input to the signal line 906, the driving TFT 901 is turned on, and the power supply line 907 and the light emitting element 904 are connected. In this state, the light emitting element 904 emits light. Note that by providing the capacitor 903, the potential of the gate electrode of the driving TFT 901 can be easily held.

  The light emitting element 904 has the same configuration as the light emitting element described in the first embodiment. Therefore, also in this embodiment, the same effect as the first embodiment, for example, the effect that the intensity of light emitted from the upper surface of the light emitting element is high can be obtained.

(Third embodiment)
FIG. 3A is a cross-sectional view for explaining the configuration of the light emitting element according to the third embodiment, and FIG. 3B is a plan view of the light emitting element. FIG. 3A shows a cross section taken along the line AA ′ of FIG. The light-emitting element shown in this embodiment has a structure in which a portion protruding above the surface of the insulating film 16 is removed from the light-emitting element shown in FIGS. For this reason, the contents described in the first embodiment are also applied to this embodiment except that the emitted light is directly emitted from the end face of the light emitting layer 19. Hereinafter, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The method for manufacturing the light emitting device according to this embodiment is as follows. First, the insulating film 16 and the opening 16a are formed on the substrate 10, and further the lower electrode 17, the p-type semiconductor layer 18, the light emitting layer 19, the n-type semiconductor layer 20, and the upper electrode 21 are formed. These forming methods are the same as those in the first embodiment.

  Next, portions of the lower electrode 17, the p-type semiconductor layer 18, the light emitting layer 19, the n-type semiconductor layer 20, and the upper electrode 21 that are located on the insulating film 16 are removed by CMP or etchback. Thereby, the end surfaces of the lower electrode 17, the p-type semiconductor layer 18, the light emitting layer 19, the n-type semiconductor layer 20, and the upper electrode 21 are substantially flush with the surface of the insulating film 16. For this reason, when viewed from a direction perpendicular to the insulating film 16, the end face of the light emitting layer 19 becomes visible, and light emitted from the light emitting layer 19 is emitted directly upward from the end face of the light emitting layer 19.

  In addition, the angle of the end surface of the light emitting layer 19 with respect to the surface of the insulating film 16 is 180 ° in this figure. Here, “the angle of the end face of the light emitting layer 19 with respect to the surface of the insulating film 16” is, for example, a cross section perpendicular to the “surface of the insulating film 16” and the “end face of the light emitting layer 19”. Considering the line segment formed by the “surface of the insulating film 16” and the line segment formed by the “end face of the light emitting layer 19”, an angle formed by the two line segments with a point extending one of the line segments and intersecting the other as a vertex. Shall. When this angle is greater than 90 ° and less than 270 °, that is, when the end face of the light emitting layer 19 is visible from above, the above-described effects can be obtained.

  As described above, according to this embodiment, the same effect as that of the first embodiment can be obtained. Moreover, since the light emitted from the light emitting layer 19 is emitted directly upward from the end face of the light emitting layer 19, the light emission efficiency is further improved.

The insulating film 16 is preferably thicker than that of the first embodiment. In this way, even if the portion located on the insulating film 16 is removed, the area where the upper electrode 21 contacts the n-type semiconductor layer 20 can be made sufficiently large.
In the circuit shown in FIG. 2, the light-emitting element 904 may have a configuration similar to that of the light-emitting element described in this embodiment.

(Fourth embodiment)
FIG. 4 is a schematic perspective view for explaining the configuration of the pixel 42 included in the display device according to the fourth embodiment. In the display device according to the present embodiment, the plurality of pixels 42 are arranged in a matrix. In the pixel 42, a plurality of light emitting elements 41 are arranged in a matrix. The light emitting element 41 has the same configuration as the light emitting element according to any one of the first to third embodiments. Therefore, the contents described in the first to third embodiments can be applied to this embodiment.

  When the pixel 42 is a square with a side of 50 μm and the light emitting element 41 is a square with a side of 4.5 μm, 6 × 6 light emitting elements 41 can be arranged in the pixel 42. In this case, the arrangement interval of the light emitting elements 41 is 3.5 μm. When the light emitting element 41 is a square having a side of 4.5 μm, the opening 16a shown in FIGS. 1 and 3 is a square having a side of 2.5 μm, and the lower electrode 17, the p-type semiconductor layer 18, the light emitting layer 19, and n The thickness of the type semiconductor layer 20 may be 200 nm, 200 nm, 500 nm, and 200 nm, respectively.

  According to this embodiment, since the light emitting element 41 of the pixel 42 has the same configuration as the light emitting element shown in any of the first to third embodiments, a display device with high light emission efficiency can be obtained. Can do.

  In addition, since the pixel 42 is configured by the plurality of light emitting elements 41, even when the brightness of the light emitting elements 41 varies, it is possible to suppress the variation in brightness of the pixels 42. Note that the causes of variations in the brightness of the light emitting elements 41 include variations in the light emitting elements 41 themselves and variations in elements that control light emission of the light emitting elements 41 (for example, TFTs).

(Fifth embodiment)
5, 6, 7 and 8 are views for explaining a method of manufacturing a semiconductor device according to the fifth embodiment of the present invention. In this manufacturing method, the light emitting element described in the first embodiment, the driving TFT (for example, the driving TFT 901 shown in FIG. 2) and the switching TFT (for example, the switching TFT 902 shown in FIG. 2) of this light emitting element. Are formed on the same substrate. For this reason, the content described in the first embodiment can also be applied to this embodiment. Hereinafter, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  First, as shown in the cross-sectional view of FIG. 5A, a tungsten film is formed over the substrate 10 by a sputtering method. The thickness of the tungsten film is, for example, 150 nm. Next, a resist pattern is formed on the tungsten film, and the tungsten film is selectively etched using the resist pattern. As a result, the gate electrode 11 a of the driving transistor and the gate electrode 11 b of the switching transistor are formed on the substrate 10. Thereafter, the resist pattern is removed.

  Next, as shown in the cross-sectional view of FIG. 5B, a gate insulating film 12 is formed on the gate electrodes 11a and 11b and the substrate 10 by a sputtering method or a CVD method. The thickness of the gate insulating film 12 is, for example, 100 nm. When a flexible substrate or a plastic substrate is used as the substrate 10, it is preferable to use a sputtering method because the film formation temperature needs to be lower than the heat resistant temperature of the substrate 10. However, when the film formation temperature can be lower than the heat resistance temperature of the substrate 10, a CVD method can also be used.

  Next, as shown in the cross-sectional view of FIG. 5C, a resist pattern is formed over the gate insulating film 12, and the gate insulating film 12 is selectively etched using the resist pattern as a mask. Thereby, the connection hole 30 located on the gate electrode 11a is formed in the gate insulating film 12. Thereafter, the resist pattern is removed.

  Next, a semiconductor film is formed over the gate insulating film 12. The thickness of this semiconductor film is, for example, 100 nm. The semiconductor film is, for example, a ZnO film, but may be a polysilicon film or an amorphous silicon film. When the semiconductor film is a ZnO film, the semiconductor film is formed by a sputtering method. In this case, since the film formation temperature is low, a flexible substrate or a plastic substrate can be used as the substrate 10.

  Next, a resist pattern is formed on the semiconductor film, and the semiconductor film is selectively etched. When the semiconductor film is a ZnO film, the semiconductor film is etched by wet etching using, for example, a hydrofluoric acid aqueous solution. Thus, an island-shaped semiconductor film 13a serving as a driving transistor, an island-shaped semiconductor film 13b serving as a switching transistor, and an island-shaped semiconductor film 13c are formed on the gate insulating film 12. The semiconductor film 13b is electrically connected to the gate electrode 11a through the connection hole 30. The semiconductor film 13 c constitutes a capacitor element 23 together with the gate electrode 11 a and the gate insulating film 12. The semiconductor film 13c is connected to the semiconductor film 13a at a portion not shown in the drawing. Thereafter, the resist pattern is removed.

  Next, as shown in the cross-sectional view of FIG. 5D, a first interlayer insulating film 14 is formed on each of the semiconductor films 13a to 13c and on the gate insulating film 12 by, for example, a sputtering method. The first interlayer insulating film 14 is a silicon oxide film, for example, and has a thickness of 500 nm, for example. Next, a resist pattern is formed on the first interlayer insulating film 14, and the first interlayer insulating film 14 is selectively etched using the resist pattern as a mask. As a result, a connection hole 31 located on the semiconductor film 13b and a connection hole 32 (shown in FIG. 6) located on the semiconductor film 13c are formed in the first interlayer insulating film. Thereafter, the resist pattern is removed.

  Next, a conductive film is formed on the first interlayer insulating film 14 by a sputtering method. The conductive film is, for example, an Al—Ti alloy. In this case, an Al—Ti alloy target is used as the sputtering target. The thickness of the conductive film is, for example, 200 nm. Next, a resist pattern is formed over the conductive film, and the conductive film is selectively etched using the resist pattern as a mask. Thereby, the signal line 15 and the power supply line 22 (shown in FIG. 6) are formed. The signal line 15 is electrically connected to the semiconductor film 13 b through the connection hole 31, and the power line 22 is electrically connected to the semiconductor films 13 a and 13 c through the connection hole 32. Thereafter, the resist pattern is removed.

  In this manner, a switching TFT and a driving TFT for controlling the light emitting element are formed. These TFTs are bottom gate type TFTs, but may be top gate type TFTs.

  Here, the configuration of the switching TFT 24 and the driving TFT 25 will be described with reference to the plan view of FIG. The switching TFT 24 includes a gate electrode 11b, a gate insulating film 12 (not shown in the figure), and a semiconductor film 13b. The semiconductor film 13 b is connected to the signal line 15 through the plurality of connection holes 31 and is connected to the gate electrode 11 a through the plurality of connection holes 30. The driving TFT 25 includes a gate electrode 11a, a gate insulating film 12, and a semiconductor film 13a. The semiconductor film 13a is connected to the semiconductor film 13c. The semiconductor film 13 c is electrically connected to the power supply line 22 through the plurality of connection holes 32. Thus, the semiconductor film 13a is electrically connected to the power supply line 22 through the semiconductor film 13c. The signal line 15 and the power supply line 22 are parallel to each other, and the gate electrode 11b is orthogonal to the signal line 15 and the power supply line 22.

  A part of the semiconductor film 13 c overlaps with a part of the gate electrode 11 a with the gate insulating film 12 interposed therebetween, and functions as the capacitor 23. The capacitor 23 functions as a capacitor that is electrically connected to the power supply line 22 and the gate electrode 11a.

  Next, as shown in FIG. 7A, the insulating film 16 is formed on the signal line 15, the power supply line 22 (shown in FIG. 6), and the first interlayer insulating film 14, for example, by sputtering. The insulating film 16 is, for example, a silicon oxide film, and the thickness thereof is, for example, not less than 1000 nm and not more than 1500 nm. Next, a resist pattern (not shown) is formed on the insulating film 16, and the insulating film 16 is etched using the resist pattern as a mask. As a result, a recess 16b is formed in the insulating film 16 above the semiconductor film 13a. The recess 16b is a substitute for the opening 16a in the first embodiment, and has a depth of, for example, 600 nm or more and 1000 nm or less. Thereafter, the resist pattern is removed.

  Next, a resist pattern is formed in the recess 16b and on the insulating film 16, and the insulating film 16 and the first interlayer insulating film 14 are etched using the resist pattern as a mask. As a result, a connection hole 33 located on the semiconductor film 13a is formed in the insulating film 16 and the first interlayer insulating film 14 located on the bottom surface of the recess 16b. Thereafter, the resist pattern is removed.

  Next, as shown in FIG. 7B, the lower electrode 17 is formed in the recess 16b. The formation method of the lower electrode 17 is the same as that of the first embodiment. Note that when the lower electrode 17 is formed, a part of the lower electrode 17 is embedded in the connection hole 33, so that the lower electrode 17 is electrically connected to the semiconductor film 13 a through the connection hole 33.

  Thereafter, the p-type semiconductor layer 18, the light emitting layer 19, the n-type semiconductor layer 20, and the upper electrode 21 are formed. These forming methods are the same as those in the first embodiment.

  Next, as shown in FIG. 8, the p-type semiconductor layer 18, the light emitting layer 19, the n-type semiconductor layer 20, and the upper electrode 21 are selectively removed. These removal methods are the same as those in the first embodiment.

  As described above, according to the fifth embodiment, the light emission efficiency of the light emitting element can be increased as in the first embodiment. Moreover, since the semiconductor films 13a and 13b constituting the TFT are made of ZnO formed by sputtering, the thermal load applied to the substrate 10 can be reduced. For this reason, a flexible substrate or a plastic substrate can be used as the substrate 10. When a flexible substrate is used as the substrate 10, a sheet display can be realized. Further, when a plastic substrate is used as the substrate 10, the plastic substrate is cheaper and lighter than a glass substrate, so that the manufacturing cost of the semiconductor device can be reduced and the semiconductor device can be reduced in weight. .

  The semiconductor film 13a of the driving TFT 25 and the semiconductor film 13b of the switching TFT 24 are each formed of ZnO, but the band gap of ZnO is as high as 3.4 eV. Therefore, unlike a Si-based TFT (with a band gap of 1.1 eV), even if visible light is irradiated, the driving TFT 25 and the switching TFT 24 do not malfunction due to photoexcitation of carriers.

  In addition, a large amount of Zn is contained in the earth's crust (70 mg / kg) and is easily available and inexpensive. Therefore, by using ZnO for both the TFT and the light emitting element, the material cost of the semiconductor device can be reduced.

  When a heat resistant substrate is used as the substrate 10, a polysilicon film or an amorphous silicon film can be used as the semiconductor films 13a and 13b. Further, as the semiconductor films 13a and 13b, organic semiconductor films such as pentacene and oligothiophene can be used.

  In addition, since ZnO has a high total transmittance of 90% or more, the gate electrodes 11a and 11b, the signal line 15, and the power supply line 22 are made of a transparent conductor (for example, ITO, GZO (ZnO into which Ga is introduced), or AZO (Al. By forming with introduced ZnO)), the semiconductor device can be made transparent. In this case, a transparent display can be realized.

  The structure of the light emitting element may be the structure shown in the third embodiment.

(Sixth embodiment)
FIG. 9 is a circuit diagram for explaining the circuit configuration of the display device according to the sixth embodiment, and FIG. 10 is a plan view for explaining the color arrangement of the fluorescent film of each pixel. This display device has a plurality of pixels arranged in a matrix. Each pixel has a circuit 910 having the same configuration as that of the second embodiment as shown in FIG. 9, and fluorescent films 912r, 912g, and 912g above the light emitting element 904 in the circuit 910 as shown in FIG. Any one of 912b is arranged. For this reason, the content described in the second embodiment can also be applied to this embodiment. The specific structure of each pixel is the same as that described in the fifth embodiment, for example.

  In this embodiment, the light emitting element 904 emits ultraviolet light, and the fluorescent film absorbs the ultraviolet light emitted by the light emitting element 904 and emits red, green, or blue light. Hereinafter, the same components as those of the second embodiment are denoted by the same reference numerals, and description thereof is omitted. In addition, the display device according to the present embodiment has a configuration other than the fluorescent films 912r, 912g, and 912b, for example, by the method described in the third embodiment. Thereafter, the fluorescent films 912r, 912g, and 912b may be disposed at predetermined positions.

Note that the fluorescent film 912r is a film that emits red light, for example, Y ₂ O ₂ S: Eu ³⁺ , La ₂ O ₂ S: Eu ³⁺ , Li (Eu, Sm) W ₂ O ₈ , or Ba ₃ MgSi. ₂ O ₈ : Eu ²⁺ , Mn ²⁺ can be used. The fluorescent film 912g is a film that emits green light, and ZnS: Cu, Al, BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , Mn ²⁺ , or SrGa ₂ S ₄ : Eu ²⁺ can be used. Further, the fluorescent film 912b is a film that emits blue light, and (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ , or (Ba, Sr) MgAl ₁₀ O ₁₇ : Eu ^2+. Can be used.

  The light emitting element 904 has the same configuration as that of the first embodiment, for example, but may have the same configuration as that of the third embodiment. Further, the arrangement of red, blue, and green, that is, the arrangement of the fluorescent films 912r, 912g, and 912b is not limited to the example shown in FIG. 10, and may be another arrangement.

  According to the present embodiment, light emitted from the light emitting element 904 is efficiently emitted from the upper surface, and thus the display device can be brightened while suppressing power consumption. In the case where the light-emitting element 904, the switching TFT 902, and the driving TFT 901 are formed using ZnO, a temperature applied to the substrate at the time of manufacturing can be reduced; therefore, a flexible substrate or a plastic substrate can be used as the substrate. In the former case, a sheet display can be realized, and in the latter case, the manufacturing cost of the display device can be reduced.

  Further, since the fluorescent films 912r, 912g, and 912b absorb ultraviolet light and emit red, green, or blue light, compared with a case where a color filter is provided on a white light source such as a white light emitting diode or a white EL element. The luminous efficiency of red, green and blue is high. In addition, since the light-emitting element 904 formed using an inorganic material is a light-emitting source, it has a longer lifetime and higher reliability than a display device using an organic EL.

  In addition, in a display device using an organic EL, it is necessary to form a light emitting layer that emits light of each color. In this embodiment, the light emitting layer is formed of one kind of material. Therefore, the manufacturing cost can be reduced as compared with the case of using the organic EL.

  Further, if a TFT is provided in each pixel as in this embodiment, low voltage driving can be performed, which is advantageous when the pixel density is increased.

  Note that although an active matrix display device in which a TFT is provided in each pixel has been described in this embodiment mode, a passive matrix light-emitting device may be used. A passive matrix display device can have a high aperture ratio because a TFT is not provided for each pixel. In the case of a display device in which emitted light is emitted to both sides of the light emitting laminate, the transmittance increases when the passive matrix type is used.

(Seventh embodiment)
FIG. 11A is a top view of a panel according to the seventh embodiment, and FIG. 11B is a cross-sectional view taken along the line AA ′ of FIG. This panel has a pixel portion 4002 in which a plurality of pixels are arranged in a matrix at the center. The configuration of each pixel included in the pixel portion 4002 is the same as the pixel of the display device included in the sixth embodiment, for example, and the configuration of the light emitting element 4011 included in each pixel is described in the first or third embodiment, for example. This is the same as the light emitting element. Each pixel may have a plurality of light emitting elements 4011 as shown in the fourth embodiment. Note that the configuration of the circuit for driving the pixels is the same as the circuit shown in the second embodiment.

  The light emitting element 4011 is covered with an interlayer insulating film 4007. A transparent electrode 4006 is formed on the interlayer insulating film 4007. The transparent electrode 4006 is electrically connected to the upper electrode of the light emitting element 4011 through a connection hole formed in the interlayer insulating film 4007. A fluorescent film 4012 is disposed on the transparent electrode 4006. A counter substrate 4013 is disposed on the fluorescent film 4012.

  Note that as the interlayer insulating film 4007, a silicon oxide film, a silicon oxynitride film, or a silicon nitride oxide film can be used. Further, a glass substrate can be used as the counter substrate 4013. As the transparent electrode 4006, ITO (Indium Tin Oxide), ITSO (indium tin oxide containing silicon oxide), IZO (Indium Zinc Oxide), GZO (ZnO into which Ga is introduced) are used. Alternatively, AZO (ZnO into which Al is introduced) can be used.

  The substrate 4001 is provided with a pixel portion 4002 and a signal line driver circuit 4003 and a scan line driver circuit 4004 which are located around the pixel portion 4002. Each of the pixel portion 4002, the signal line driver circuit 4003, and the scan line driver circuit 4004 includes a plurality of TFTs. FIG. 11B illustrates a TFT 4010 included in the pixel portion 4002 and a TFT 4008 included in the signal line driver circuit 4003. In this figure, a top gate type TFT is shown, but a bottom gate type TFT (illustrated in the fifth embodiment) may be used. Note that the source or drain of the TFT 4010 is electrically connected to the lower electrode of the light emitting element 4011.

  In addition, the wiring 4014 is provided on the panel. The lead wiring 4014 is a wiring for supplying a signal or a power supply voltage to the signal line driver circuit 4003 and the scanning line driver circuit 4004. The routing wiring 4014 is connected to the connection terminal 4016 located in the peripheral portion of the substrate 4001 through the routing wirings 4015a and 4015b. The connection terminal 4016 is electrically connected to a terminal included in an FPC (flexible printed circuit) 4018 through an anisotropic conductive film 4019.

  According to the present embodiment, it is possible to obtain the same effect as that of the sixth embodiment, for example, the effect of high luminous efficiency.

  Note that the signal line driver circuit 4003 is not necessarily formed over the substrate 4001. In this case, a TFT having a switching function is formed over the substrate 4001, and an IC (module) connected to the TFT is mounted on the panel using an FPC or the like. This IC has a function of inputting a video signal to the TFT and controlling the TFT.

(Eighth embodiment)
Each of FIG. 12 and FIG. 13 is a circuit diagram for explaining a circuit configuration of a panel or a module according to the eighth embodiment. These drawings show modifications of the circuit configuration of the panel or module shown in the seventh embodiment. The light emitting element 1405 corresponds to the light emitting element 4011 in the seventh embodiment. The switching TFT 1401, the driving TFT 1404, and the capacitor element 1402 correspond to the switching TFT 902, the driving TFT 901, and the capacitor element 903 in the second embodiment, respectively. Therefore, the contents described in the second embodiment can also be applied to this embodiment.

  The switching TFT 1401 is a TFT that controls input of a video signal to the pixel. When the switching TFT 1401 is turned on, the video signal is input into the pixel. Then, the voltage of the input video signal is held in the capacitor element 1402. Note that in the case where a gate capacity or the like is sufficient for holding a video signal voltage, the capacitor 1402 is not necessarily provided.

  In the circuit illustrated in FIG. 12A, the signal line 1410 and the power supply lines 1411 and 1412 extend in the column direction, and the scanning line 1414 extends in the row direction. Further, a current control TFT 1403 is connected in series between the driving TFT 1404 and the light emitting element 1405. The gate electrode of the current control TFT 1403 is electrically connected to the power supply line 1412.

  The circuit illustrated in FIG. 12B has a structure similar to that of the circuit illustrated in FIG. 12A except that the power supply line 1412 extends in the row direction. That is, FIG. 12B is an equivalent circuit diagram of FIG. However, when the power supply line 1412 extends in the column direction (in the case of FIG. 12A) and in the case of extension in the row direction (in the case of FIG. 12B), the power supply line 1412 is provided in different layers. . Here, in order to show that the power supply line 1412 is arranged in a different layer, it is shown separately in FIGS. 12 (A) and 12 (B).

  A feature of the circuits shown in FIGS. 12A and 12B is that a driving TFT 1404 and a current control TFT 1403 are connected in series in a pixel. The current control TFT 1403 operates in a saturation region and has a function of controlling a current value flowing through the light emitting element 1405. The ratio (L1 / W1) of the channel length (L1) to the channel width (W1) of the current control TFT 1403 is 5000 times the ratio (L2 / W2) of the channel length (L2) to the channel width (W2) of the driving TFT 1404. It is preferable to make it 6000 times or less.

  These two TFTs 1403 and 1404 preferably have the same conductivity type (for example, an n-channel TFT) in terms of the manufacturing process. The driving TFT 1404 can be not only an enhanced TFT but also a depletion TFT. This is because, since the current control TFT 1403 operates in the saturation region, a minute change in Vgs of the driving TFT 1404 does not affect the value of the current flowing through the light emitting element 1405. That is, the current value of the light emitting element 1405 is determined by the current control TFT 1403 operating in the saturation region. With such a configuration, it is possible to suppress variation in light emission characteristics due to variation in TFT characteristics. If each pixel is formed of a plurality of light emitting elements as shown in the fourth embodiment, the variation in light emission between the pixels can be further suppressed, so that the image quality and reliability of the panel can be further improved. .

  The circuit illustrated in FIG. 12C has a structure similar to that of the circuit illustrated in FIG. 12A except that a TFT 1406 and a scanning line 1415 are added. The circuit illustrated in FIG. 12D has a structure similar to that of the circuit illustrated in FIG. 12B except that a TFT 1406 and a scanning line 1415 are added. The scanning line 1415 extends in the row direction.

  The TFT 1406 is provided in parallel with the capacitor 1402. In addition, the gate electrode of the TFT 1406 is electrically connected to the scanning line 1415, and on / off is controlled by the scanning line 1415. When the TFT 1406 is turned on, the charge held in the capacitor element 1402 is discharged, and the driving TFT 1404 is turned off. That is, by providing the TFT 1406, a state in which no current flows through the light-emitting element 1405 can be forcibly created. Therefore, the TFT 1406 can be called an erasing TFT.

  As described above, in the circuits shown in FIGS. 12C and 12D, the lighting period can be started at the same time as or immediately after the start of the writing period without waiting for signal writing to all pixels. Can be improved.

  The circuit shown in FIG. 12E has the same structure as the circuit shown in FIGS. 12C and 12D except that the power supply line 1412 and the current control TFT 1403 are not provided. Even in this case, the duty ratio can be improved in the same manner as the circuits shown in FIGS.

  In the circuit illustrated in FIG. 13, a switching TFT 1401, a capacitor element 1402, a driving TFT 1404, and a light emitting element 1405 are provided in the pixel portion 1500. Diodes 1561 and 1562 are connected to the signal line 1410. The diodes 1561 and 1562 are formed in the same process as the switching TFT 1401 and the driving TFT 1404, for example, and include a gate electrode, a semiconductor layer, a source electrode, a drain electrode, and the like. The diodes 1561 and 1562 operate as diodes when a gate electrode and a drain electrode or a source electrode are electrically connected to each other.

  In the diode 1561, one of the gate electrode, the drain electrode, and the source electrode is electrically connected to the common potential line 1554, and the other of the drain electrode and the source electrode is connected to the signal line 1410. In the diode 1562, one of a gate electrode, a drain electrode, and a source electrode is electrically connected to the signal line 1410, and the other of the drain electrode and the source electrode is connected to a common potential line 1555. The common potential lines 1554 and 1555 are arranged in the same layer as the gate electrode, and are formed in the same process as the gate electrode. Therefore, in order to connect the source electrode or the drain electrode of the diodes 1561 and 1562 to the common potential line, it is necessary to form a connection hole in the gate insulating film.

  A diode and a common potential line are also formed in the scanning line 1414, and these configurations are the same as the diodes 1561 and 1562 and the common potential lines 1554 and 1555.

  According to the circuit shown in FIG. 13, the protection diode can be formed in the same process as each TFT. Note that the position where the protective diode is formed is not limited thereto, and the protective diode can be formed between the driver circuit and the pixel.

(Ninth embodiment)
An electronic apparatus according to a ninth embodiment will be described with reference to FIGS. 14 and 15. This electronic apparatus has the display device or panel described in any of the sixth to eighth embodiments. As this electronic device, a video camera, a digital camera, a goggle type display (head mounted display), a navigation system, a sound reproduction device (car audio component, etc.), a computer, a game device, a portable information terminal (mobile computer, cellular phone, portable type) A game machine or an electronic book), an image playback device provided with a recording medium (specifically, a device provided with a display capable of playing back a recording medium such as a Digital Versatile Disc (DVD) and displaying the image). It is done. Specific examples of these electronic devices are shown in FIGS.

  FIG. 14A shows a monitor of a television receiver or a personal computer. A housing 3001, a display portion 3003, a speaker portion 3004, and the like are included. The display portion 3003 is provided with an active matrix display device. As the display device, the display device or panel described in the sixth to eighth embodiments is used. A light emitting element included in a display device or a panel is colored in R (red), G (green), or B (blue) through a fluorescent film, and thus has higher luminous efficiency than a color filter. . In addition, since an inorganic semiconductor is used for the light-emitting element, the lifetime is longer than that in the case where an organic EL is used. Note that when a structure having a plurality of light emitting elements for each pixel is used as shown in the fourth embodiment, variation in light emission between pixels is suppressed, display spots are reduced, and a television or monitor with high image quality and reliability is provided. Obtainable.

  FIG. 14B illustrates a mobile phone, which includes a main body 3101, a housing 3102, a display portion 3103, a sound input portion 3104, a sound output portion 3105, operation keys 3106, an antenna 3108, and the like. The display portion 3103 is provided with an active matrix display device. For this display device, the display device or panel described in the sixth to eighth embodiments is used. Since the light emitting element included in the display device or the panel is colored in R, G, or B through the fluorescent film, the light emitting efficiency is higher than that in the case of using a color filter. In addition, since an inorganic semiconductor is used for the light-emitting element, the lifetime is longer than that in the case where an organic EL is used. Note that, when a configuration having a plurality of light emitting elements for each pixel as shown in the fourth embodiment, variation in light emission between pixels is suppressed, display spots are reduced, and a mobile phone with high image quality and reliability is obtained. be able to.

  FIG. 14C illustrates a computer. A main body 3201 is provided with a keyboard 3204, an external connection port 3205, a pointing mouse 3206, and the like. In addition, a housing 3202 having a display portion 3203 is attached to the main body 3201. The display portion 3203 is provided with an active matrix display device. For this display device, the display device or panel described in the sixth to eighth embodiments is used. Since the light emitting element included in the display device or the panel is colored in R, G, or B through the fluorescent film, the light emitting efficiency is higher than that in the case of using a color filter. In addition, since an inorganic semiconductor is used for the light-emitting element, the lifetime is longer than that in the case where an organic EL is used. Note that, when a configuration having a plurality of light emitting elements for each pixel as shown in the fourth embodiment, variation in light emission between pixels is suppressed, display spots are reduced, and a computer with high image quality and reliability can be obtained. Can do.

  FIG. 14D illustrates a mobile computer, which includes a main body 3301, a display portion 3302, a switch 3303, operation keys 3304, an infrared port 3305, and the like. The display portion 3302 is provided with an active matrix display device. For this display device, the display device or panel described in the sixth to eighth embodiments is used. Since the light emitting element included in the display device or the panel is colored in R, G, or B through the fluorescent film, the light emitting efficiency is higher than that in the case of using a color filter. In addition, since an inorganic semiconductor is used for the light-emitting element, the lifetime is longer than that in the case where an organic EL is used. Note that, when a configuration having a plurality of light emitting elements for each pixel as shown in the fourth embodiment, variation in light emission between pixels is suppressed, display spots are reduced, and a mobile computer with high image quality and reliability is obtained. be able to.

  FIG. 14E illustrates a portable game machine, which includes a housing 3401, a display portion 3402, speaker portions 3403, operation keys 3404, a recording medium insertion portion 3405, and the like. The display portion 3402 is provided with an active matrix display device. For this display device, the display device or panel described in the sixth to eighth embodiments is used. Since the light emitting element included in the display device or the panel is colored in R, G, or B through the fluorescent film, the light emitting efficiency is higher than that in the case of using a color filter. In addition, since an inorganic semiconductor is used for the light-emitting element, the lifetime is longer than that in the case where an organic EL is used. Note that when a structure having a plurality of light-emitting elements for each pixel is used as shown in the fourth embodiment, variation in light emission between pixels is suppressed, display spots are reduced, and a portable game with high image quality and reliability. You can get a chance.

  FIG. 15 shows a paper display, which includes a main body 3110, a pixel portion 3111, a driver IC 3112, a receiving device 3113, a film battery 3114, and the like. The receiving device 3113 can receive a signal from an infrared communication port (not shown) included in the mobile communication terminal illustrated in FIG. The pixel portion 3111 is provided with an active matrix display device. For this display device, the display device or panel described in the sixth to eighth embodiments is used. Since the light emitting element included in the display device or the panel is colored in R, G, or B through the fluorescent film, the light emitting efficiency is higher than that in the case of using a color filter. In addition, since an inorganic semiconductor is used for the light-emitting element, the lifetime is longer than that in the case where an organic EL is used. Note that, when a configuration having a plurality of light emitting elements for each pixel as shown in the fourth embodiment, variation in light emission between pixels is suppressed, so that display spots are reduced, and a paper display with high image quality and reliability is obtained. be able to.

  Thus, the applicable range of the present invention is extremely wide and can be used for electronic devices in various fields.

  Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

(A) is sectional drawing for demonstrating the structure of the light emitting element which concerns on 1st Embodiment, (B) is a top view. The circuit diagram for demonstrating the structure of the drive circuit of the light emitting element which concerns on 2nd Embodiment. (A) is sectional drawing for demonstrating the structure of the light emitting element which concerns on 3rd Embodiment, (B) is a top view. The perspective schematic diagram for demonstrating the structure of the pixel 42 which the display apparatus which concerns on 4th Embodiment has. The figure for demonstrating the manufacturing method of the semiconductor device which concerns on 5th Embodiment. The figure for demonstrating the manufacturing method of the semiconductor device which concerns on 5th Embodiment. The figure for demonstrating the manufacturing method of the semiconductor device which concerns on 5th Embodiment. The figure for demonstrating the manufacturing method of the semiconductor device which concerns on 5th Embodiment. The circuit diagram for demonstrating the circuit structure of the display apparatus concerning 6th Embodiment. The top view for demonstrating the arrangement | sequence of the color of the fluorescent film which each pixel has. (A) is a top view of the panel which concerns on 7th Embodiment, (B) is AA 'sectional drawing of (A). The circuit diagram for demonstrating the circuit structure of the panel or module which concerns on 8th Embodiment. The circuit diagram for demonstrating the circuit structure of the panel or module which concerns on 8th Embodiment. The perspective view for demonstrating the structure of the electronic device which concerns on 9th Embodiment. The perspective view for demonstrating the structure of the electronic device which concerns on 9th Embodiment. Sectional drawing for demonstrating the structure of the conventional light emitting element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Board | substrate, 16 ... Insulating layer, 16a ... Opening part, 16b ... Groove, 17 ... Lower electrode, 17a ... 1st recessed part, 18 ... P-type semiconductor layer, 18a ... 2nd recessed part, 19 ... Light emitting layer, 19a ... third recess, 20 ... n-type semiconductor layer, 20a ... fourth recess, 21 ... upper electrode

Claims (23)

A first recess or opening formed in the insulating film;
Formed on the insulating film located around the first recess or opening, and on the bottom and side surfaces of the first recess or opening, and located in the first recess or in the opening. A first electrode having a recess;
A first conductivity type semiconductor layer formed on the first electrode and having a third recess located in the second recess;
A light emitting layer formed on the first conductivity type semiconductor layer and having a fourth recess located in the third recess;
A second conductivity type semiconductor layer formed on the light emitting layer and having a fifth recess located in the fourth recess;
A second electrode formed on the second conductivity type semiconductor layer constituting the bottom and side surfaces of the fifth recess;
A semiconductor device comprising: The band gap of the second conductivity type semiconductor layer is less than or equal to the band gap of the light emitting layer,
The semiconductor device according to claim 1, wherein a thickness of the second conductivity type semiconductor layer is thinner than a thickness of the light emitting layer. A first recess or opening formed in the insulating film;
A first electrode having a second recess formed on a bottom surface and a side surface of the first recess or opening, and located in the first recess or opening;
A first conductivity type semiconductor layer formed on the first electrode and having a third recess located in the second recess;
A light emitting layer formed on the first conductivity type semiconductor layer and having a fourth recess located in the third recess;
A second conductivity type semiconductor layer formed on the light emitting layer and having a fifth recess located in the fourth recess;
A second electrode formed on the second conductivity type semiconductor layer constituting the bottom and side surfaces of the fifth recess;
And the angle of the end face of the light emitting layer with respect to the surface of the insulating film is more than 90 ° and less than 270 °. The EML semiconductor device according to claim 1 or 3 the band gap is composed of more materials 3 eV. The semiconductor device according to claim 4, wherein the material constituting the light emitting layer is ZnO, ZnS, GaN, SiC, or Mg _1-X Zn _X O.   The material constituting the first conductivity type semiconductor layer and the material constituting the second conductivity type semiconductor layer each have a larger band gap than the material constituting the light emitting layer. The semiconductor device according to claim 1.   The semiconductor device according to claim 6, wherein the light emitting layer has a thickness of 10 nm or less. The material constituting the light emitting layer is ZnO, and the material constituting the first conductivity type semiconductor layer and the material constituting the second conductivity type semiconductor layer are Mg _1-X Zn into which impurities are introduced. The semiconductor device according to claim 6, wherein the semiconductor device is _{X 2} O.   The semiconductor device according to claim 1, wherein the first electrode has a reflectance of 90% or more of light emitted from the light emitting layer. A thin film transistor formed on a substrate;
An insulating film located above or above the thin film transistor;
A light emitting element formed on the insulating film and controlled in light emission by the thin film transistor;
Comprising
The light emitting element is
Formed on the insulating film located around the first recess or opening formed in the insulating film, and on the bottom and side surfaces of the first recess or opening, and in the first recess or opening A first electrode having a second recess located in
A first conductivity type semiconductor layer formed on the first electrode and having a third recess located in the second recess;
A light emitting layer formed on the first conductivity type semiconductor layer and having a fourth recess located in the third recess;
A second conductivity type semiconductor layer formed on the light emitting layer and having a fifth recess located in the fourth recess;
A second electrode formed on the second conductivity type semiconductor layer constituting the bottom and side surfaces of the fifth recess;
A semiconductor device comprising: A thin film transistor formed on a substrate;
An insulating film located above or above the thin film transistor;
A light emitting element formed on the insulating film and controlled in light emission by the thin film transistor;
Comprising
The light emitting element is
A first electrode having a second recess formed in a bottom surface and a side surface of the first recess or opening formed in the insulating film and positioned in the first recess or opening;
A first conductivity type semiconductor layer formed on the first electrode and having a third recess located in the second recess;
A light emitting layer formed on the first conductivity type semiconductor layer and having a fourth recess located in the third recess;
A second conductivity type semiconductor layer formed on the light emitting layer and having a fifth recess located in the fourth recess;
A second electrode formed on the second conductivity type semiconductor layer constituting the bottom and side surfaces of the fifth recess;
And the angle of the end face of the light emitting layer with respect to the surface of the insulating film is more than 90 ° and less than 270 °. The thin film transistor
An island-shaped ZnO film;
An impurity region formed in the ZnO film and serving as a source or drain of the thin film transistor;
The semiconductor device according to claim 10, comprising:   The semiconductor device according to claim 10, wherein the substrate is a flexible substrate or a plastic substrate. A thin film transistor formed on a substrate;
An insulating film located above or above the thin film transistor;
A light emitting element that is formed on the insulating film, emits ultraviolet light, and the light emission is controlled by the thin film transistor;
A phosphor that is located above or above the light emitting element, absorbs ultraviolet light emitted by the light emitting element, and emits visible light; and
Comprising
The light emitting element is
Formed on the insulating film located around the first recess or opening formed in the insulating film, and on the bottom and side surfaces of the first recess or opening, and in the first recess or opening A first electrode having a second recess located in
A first conductivity type semiconductor layer formed on the first electrode and having a third recess located in the second recess;
A light emitting layer formed on the first conductivity type semiconductor layer and having a fourth recess located in the third recess;
A second conductivity type semiconductor layer formed on the light emitting layer and having a fifth recess located in the fourth recess;
A second electrode formed on the second conductivity type semiconductor layer constituting the bottom and side surfaces of the fifth recess;
A display device. A thin film transistor formed on a substrate;
An insulating film located above or above the thin film transistor;
A light emitting element that is formed on the insulating film, emits ultraviolet light, and the light emission is controlled by the thin film transistor;
A phosphor that is located above or above the light emitting element, absorbs ultraviolet light emitted by the light emitting element, and emits visible light; and
Comprising
The light emitting element is
A first electrode having a second recess formed in a bottom surface and a side surface of the first recess or opening formed in the insulating film and positioned in the first recess or opening;
A first conductivity type semiconductor layer formed on the first electrode and having a third recess located in the second recess;
A light emitting layer formed on the first conductivity type semiconductor layer and having a fourth recess located in the third recess;
A second conductivity type semiconductor layer formed on the light emitting layer and having a fifth recess located in the fourth recess;
A second electrode formed on the second conductivity type semiconductor layer constituting the bottom and side surfaces of the fifth recess;
And the angle of the end face of the light emitting layer with respect to the surface of the insulating film is more than 90 ° and less than 270 °. The thin film transistor
An island-shaped ZnO film;
An impurity region formed in the ZnO film and serving as a source or drain of the thin film transistor;
The display device according to claim 14 or 15, further comprising:   The display device according to claim 14, wherein the substrate is a flexible substrate or a plastic substrate.   An electronic apparatus comprising the semiconductor device according to claim 1.   The electronic device which comprises the display apparatus as described in any one of Claims 14-17. Forming a first recess or opening in the insulating film;
Forming a first conductive film on the insulating film and on the bottom and side surfaces of the first recess or opening, thereby forming a second recess located in the first recess or in the opening;
Forming a first conductivity type semiconductor layer on the first conductive film to form a third recess located in the second recess;
Forming a light emitting layer on the semiconductor layer of the first conductivity type to form a fourth recess located in the third recess;
Forming a second conductivity type semiconductor layer on the light emitting layer, thereby forming a fifth recess located in the fourth recess;
Forming a second conductive film on the second conductive type semiconductor layer;
Of the first and second conductive films, the first conductive type semiconductor layer, the second conductive type semiconductor layer, and the light emitting layer, a portion located on the insulating film is removed by selective etching. A method for manufacturing a semiconductor device. Forming a first recess or opening in the insulating film;
Forming a first conductive film on the insulating film and on the bottom and side surfaces of the first recess or opening, thereby forming a second recess located in the first recess or in the opening;
Forming a first conductivity type semiconductor layer on the first conductive film to form a third recess located in the second recess;
Forming a light emitting layer on the semiconductor layer of the first conductivity type to form a fourth recess located in the third recess;
Forming a second conductivity type semiconductor layer on the light emitting layer, thereby forming a fifth recess located in the fourth recess;
Forming a second conductive film on the second conductive type semiconductor layer;
Of the first and second conductive films, the first conductive type semiconductor layer, the second conductive type semiconductor layer, and the light emitting layer, a portion located on the insulating film is removed by polishing or etch back. A method for manufacturing a semiconductor device. A thin film transistor is formed on the substrate,
Forming an insulating film on the thin film transistor;
Forming a first recess located above the thin film transistor in the insulating film;
Forming a connection hole located on a source or drain of the thin film transistor on a bottom surface of the first recess;
A first conductive film electrically connected to the source or drain via the connection hole is formed on the insulating film and on a bottom surface and a side surface of the first recess, thereby forming the first recess in the first recess. Forming a second recess located;
Forming a first conductivity type semiconductor layer on the first conductive film to form a third recess located in the second recess;
Forming a light emitting layer on the semiconductor layer of the first conductivity type to form a fourth recess located in the third recess;
Forming a second conductivity type semiconductor layer on the light emitting layer, thereby forming a fifth recess located in the fourth recess;
Forming a second conductive film on the second conductive type semiconductor layer;
Of the first and second conductive films, the first conductive type semiconductor layer, the second conductive type semiconductor layer, and the light emitting layer, a portion located on the insulating film is removed by selective etching. A method for manufacturing a semiconductor device. A thin film transistor is formed on the substrate,
Forming an insulating film on the thin film transistor;
Forming a first recess located above the thin film transistor in the insulating film;
Forming a connection hole located on a source or drain of the thin film transistor on a bottom surface of the first recess;
A first conductive film electrically connected to the source or drain via the connection hole is formed on the insulating film and on a bottom surface and a side surface of the first recess, thereby forming the first recess in the first recess. Forming a second recess located;
Forming a first conductivity type semiconductor layer on the first conductive film to form a third recess located in the second recess;
Forming a light emitting layer on the semiconductor layer of the first conductivity type to form a fourth recess located in the third recess;
Forming a second conductivity type semiconductor layer on the light emitting layer, thereby forming a fifth recess located in the fourth recess;
Forming a second conductive film on the second conductive type semiconductor layer;
Of the first and second conductive films, the first conductive type semiconductor layer, the second conductive type semiconductor layer, and the light emitting layer, a portion located on the insulating film is removed by polishing or etch back. A method for manufacturing a semiconductor device.

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