KR20090066644A - Thermalelectronic emission apparatus using micro-heater and method of manufacturing the same - Google Patents

Abstract

A thermal electronic emission apparatus using micro-heater and a method of manufacturing the same are provided to emit thermal electron in a micro size region by forming a thermal electron emitting layer on a micro heater. A thermionic emission apparatus(101) comprises the substrate(10), the micro heater, and the thermionic emission layer(30). The micro heater is arranged in the top of the substrate. The micro heater comprises the heating portion(21) and plurality of supporters(23). It seperates from substrate with the space and the heating portion is arranged. A plurality of supporters supports the heating portion. The thermionic emission layer is formed on the micro heater. By using the heat generated from the micro heater, the thermionic emission layer emits thermo electron. It is made of the material having the work function which the thermionic emission layer is smaller than the work function of the material of the heating portion.

Description

Thermoelectronic emission apparatus using micro-heater and method of manufacturing the same}

The present invention relates to a hot electron emission device using a micro heater and a method for manufacturing the same.

Hot electron emission is a phenomenon in which electrons are emitted from a metal or semiconductor surface heated to a high temperature. Electrons, energized by heat, are separated from atoms and protrude from solid surfaces. They are applied to vacuum tubes and discharge tubes. To remove an electron from a metal, at least as much energy as a work function must be applied.

On the other hand, the heat electron emission source used in cathode-ray tube TV or X-ray source, etc., the heater itself provides heat to the heat ion cathode is bulk, and micro-sized hot electron emission cannot be expected. Therefore, it is difficult to be applied to electronic devices such as vacuum tube transistors, electron emission displays, electron beam-based SEMs, and TEMs requiring micro-sized hot electron emission.

In addition, in order to be applied as a hot electron emission source of a large area display, a large area planar hot electron emission should be possible. However, it is difficult to manufacture a planar hot electron emission source with a conventional heater.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a hot electron emission apparatus capable of micro-sized or planar hot electron emission.

It is also an object of the present invention to provide a method for manufacturing the above-described hot electron emission device.

The hot electron emission device according to the present invention for achieving the above object includes a substrate, a micro heater, and a hot electron emission device. The micro heater is provided on the substrate, and the hot electron emission layer is provided on the micro heater to receive heat generated from the micro heater to emit hot electrons.

The micro heater includes a heating part spaced apart from the substrate; And a plurality of supports that support the heating unit and are spaced apart from each other.

According to an embodiment of the present invention, the heating portion extends in one direction on the substrate, and the plurality of supports are partially provided between the heating portion and the substrate to support the heating portion.

According to an embodiment of the present invention, the micro heater further includes a plurality of connection parts respectively extending from both sides of the heating part and spaced apart from each other along the longitudinal direction of the heating part. Here, the plurality of supports are respectively provided under the plurality of connecting portions to support the heating unit.

According to an embodiment of the present invention, the hot electron emission layer may be partially provided in the heating unit.

The hot electron emission device of the present invention may further include a charge preventing layer which is applied to the substrate and the plurality of supports, and prevents the hot electrons emitted from the hot electron emission layer from being charged. The charge preventing layer is made of a material having a specific resistance value of 10 ³ Ωcm ~ 10 ⁹ Ωcm.

The hot electron emission device of the present invention further includes a plurality of gates respectively present on the substrate so as to be orthogonal to the heating portion at the bottom of the heating portion, spaced apart from the plurality of supports, and on / off hot electron emission from the hot electron emission layer. Can be.

According to an embodiment of the present invention, at least two micro heaters may be arranged in parallel with each other.

In another aspect of the invention, the hot electron emission device is a substrate; A micro heater provided on the substrate; And a hot electron emission layer applied to the substrate and the micro heater and receiving heat generated from the micro heater to emit hot electrons. The hot electron emission layer is composed of a hot electron emission material and a charge preventing material.

The present invention also provides a method of manufacturing the above-described hot electron emission device. Method for producing a hot electron emission device according to an aspect of the present invention is as follows. A micro heater is formed on the substrate. A hot electron emitting material that receives heat generated from the micro heater and emits hot electrons is coated on the micro heater.

The method of manufacturing a hot electron emission device of the present invention may further include applying a charge preventing layer on the substrate and the plurality of supports to prevent the emitted hot electrons from being charged.

According to an embodiment of the present invention, before the forming of the micro heater, the method may further include forming a gate on / off the hot electron emission from the hot electron emission material on the substrate.

According to another aspect of the present invention, a method of manufacturing a hot electron emission device is as follows. A micro heater is formed on the substrate. A mixture of a hot electron emission material that receives heat generated from the micro heater to emit hot electrons and a charge preventing material that prevents the discharged hot electrons from being charged is applied to the micro heater.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited by the following examples.

FIG. 1A is a perspective view illustrating a hot electron emission device according to an exemplary embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along the line II ′ of FIG. 1A.

1A and 1B, a hot electron emission device 101 according to an embodiment of the present invention includes a substrate 10, a micro heater 20, and a hot electron emission layer 30.

 The micro heater 20 is provided on the substrate 10. The hot electron emission layer 30 is provided on the micro heater 20, and receives heat generated from the micro heater 20 to emit hot electrons.

According to an embodiment of the present invention, the micro heater 20 includes a heating part 21, a plurality of connecting parts 22, and a plurality of supports 23. The heating part 21 is spaced apart from the substrate 10 on the substrate 10 and extends in one direction D1. The heating unit 21 may be made of molybdenum, tungsten, silicon carbide, and the like, and emit light and generate heat by applying power.

The substrate 10 may be made of a silicon wafer or a glass material. In particular, when the substrate 10 is made of a glass material, it transmits radiant heat (visible light or IR), thereby enabling high temperature heating.

The plurality of connection parts 22 are arranged to be spaced apart from each other along the longitudinal direction D1 of the heating part 21 on the substrate 10, and the heating part 21 from both sides of the heating part 21. Extend in the direction D2 inclined in the longitudinal direction D1. As shown in FIG. 1, the plurality of connection parts 22 are provided at both sides of the heating part 21. In the present embodiment, the plurality of connection parts 22 extend in the direction orthogonal to the longitudinal direction D1 of the heating part 21. In addition, an example in which the plurality of connection parts 22 are provided symmetrically with respect to the heating part 21 is described. However, the plurality of connection parts 22 may be provided on both sides of the heating part 21 with respect to the heating part 21. The plurality of connection parts 22 are made of the same material as the material of the heating part 21 and are integrally formed with the heating part 21 through the same process.

The plurality of supports 23 are respectively provided between the substrate 10 and the plurality of connection parts 22, and the heating part 10 and the plurality of connection parts (below) of the plurality of connection parts 22. 22). The plurality of supports 23 are partially provided at each lower portion of the plurality of connecting portions 22, and partially contact the plurality of connecting portions 22. Here, each of the plurality of connection parts 22 is divided into a first area A1 and a second area A2. The first area A1 corresponds to a contact area CA in which the plurality of connecting portions 22 and the plurality of supports 23 respectively contact each other. The second region A2 exists between the heating unit 10 and the first region A1.

In the embodiment of the present invention, an example in which the plurality of supports 23 are provided at the lower portions of the respective ends of the plurality of connecting portions 22 far from the heating portion 21 will be described. In this case, each first region A1 of the plurality of connecting portions 22 corresponds to each end of the plurality of connecting portions 22.

For reference, although the first area A1 and the contact area CA of the plurality of connection parts 22 are shown in a circle in the drawings of the present embodiment, the first area A1 or the contact area ( The shape of CA) may be a square or other shape that is not circular.

Meanwhile, the plurality of supports 23 may be made of a material having a low thermal conductivity in order to prevent loss of heat generated from the heating unit 21. For example, the plurality of supports 40 may be made of SiOx.

As shown in FIGS. 1A and 1B, a plurality of connecting portions 22 are supported by the plurality of supports 23, such that a heating portion 21 integrally formed with the plurality of connecting portions 22 is the plurality of supports. It can be supported by the plurality of supports 23 without contact with (23).

In addition, since the heating unit 21 and the plurality of supports 23 are spaced apart from each other by the plurality of connection units 22, each shape of the plurality of supports 23 is a temperature of the heating unit 21. Does not affect distribution Thus, the heating unit 21 may maintain a uniform temperature distribution.

Furthermore, even if one of the plurality of connecting portions 22 is disconnected in the process of forming the micro heater 20 or is cut off during the use of the micro heater 20, the heating portion 21 is different from the other plurality. It is connected to the connecting portion 22 of the support 23 is supported by the plurality of it can stably generate heat.

The hot electron emission layer 30 receives heat generated from the heating part 21 to emit hot electrons. When energy of a work function or more is applied to the hot electron emission layer 30, hot electrons are emitted from the surface of the hot electron emission layer 30. Accordingly, the hot electron emission layer 30 is formed using a metal capable of emitting hot electrons by heating, or a hot electron emission material such as a semiconductor material. In particular, the hot electron emission layer 30 may emit hot electrons at a lower temperature as the work function value of the hot electron emission material constituting the hot electron emission layer 30 is smaller. Examples of materials having a small work function include BaSrO, BaO or LaB ₆ . Therefore, when the hot electron emission layer 30 is formed of such a material, since the energy required for hot electron emission is small, the temperature of the heating unit can be lowered. As a result, power consumption of the hot electron emission device 101 can be reduced.

In addition, the hot electron emission material constituting the hot electron emission layer 30 has a work function smaller than the work function of the material constituting the heating unit 21. This is because high temperature heating is difficult when the work function of the material forming the heating part 21 is equal to or less than the work function of the hot electron emission material.

The hot electron emission layer 30 may be formed by applying the hot electron emission material by chemical vapor deposition, physical vapor deposition, electroplating, dipping, or the like. have.

In the present embodiment, as illustrated in FIG. 1B, an example in which the hot electron emission layer 30 is formed on the surfaces of the heating unit 21 and the plurality of connection units 22 is described. According to the method of applying the hot electron emission material, The surfaces of the plurality of supports 23 and the top surface of the substrate 10 may be formed together. In addition, by applying the hot electron emission material to a portion of the heating unit 21, it is possible to selectively control the region in which the hot electrons are emitted (see Fig. 2).

As such, by forming the hot electron emission layer 30 in the micro heater 20, hot electrons may be emitted in a micro size region. In addition, since the heating part 21 of the micro heater 20 has a uniform temperature distribution, the hot electron emission layer 30 may receive heat of a uniform temperature from the heating part 21.

In addition, if two or more micro heaters 20 are arranged on the substrate 10 to form a micro heater array, a large area of the heater is possible through this. As a result, hot electrons can be emitted in a planar manner.

2 is a plan view showing a hot electron emission apparatus according to another embodiment of the present invention. Of the components illustrated in FIG. 2, the same components as those illustrated in FIGS. 1A and 1B are denoted by the same reference numeral, and detailed description thereof will be omitted.

The substrate 10 and the micro heater 20 of the heat electron emission device 102 of this embodiment are the same as the substrate 10 and the micro heater 20 shown in FIGS. 1A and 1B. However, the hot electron emission layer 30 may be selectively controlled by forming only the portion of the heating unit 21. As a result, the application range of the hot electron emission device 102 of the present invention can be broadened.

On the other hand, the structure of the micro heater 20 is explained in more detail.

2, the widths W1 and W2 of the plurality of connecting parts 22, the length L1 of the second area A2 of the plurality of connecting parts 22, and the separation distance L2 between the plurality of connecting parts 22. ), The width W3 of the heating part 21 and the width W4 of the contact area CA are shown.

In the micro heater 20 of the present embodiment, the area of the heat transfer area between the heating part 21 and the plurality of connection parts 22 and the heat transfer between the plurality of connection parts 22 and the plurality of supports 23 is reduced, preferably. Minimizing the limit to maintain the support can reduce the power consumed to drive the micro heater 20.

The thermal conductivity Q is determined by the following equation.

The thermal conductivity Q becomes smaller as the cross-sectional area A becomes smaller, and becomes smaller as the heat transfer distance dX becomes larger. Accordingly, the longer the thermal conductivity Q transmitted from both sides of the heating part 21 to the plurality of connection parts 22 is, the longer the length L1 of the second area A2 of the plurality of connection parts 22 is. The smaller the width W1, W2 of the plurality of connecting portions 22 is, the smaller the size becomes. In addition, the larger the separation distance L2 between the plurality of connecting portions 22, the smaller the thermal conductivity Q transmitted to each of the plurality of connecting portions 22 from both sides of the heating portion 21. The reason is that in the heating part 21 having a constant length, as the distance L2 between the plurality of connecting parts 22 increases, the number of the plurality of connecting parts 22 connected to the heating part 21 decreases. This is because the area of the connecting portion 22 is reduced.

Similarly, the thermal conductivity Q transmitted from the plurality of connecting portions 22 to the plurality of supports 23 respectively becomes smaller as the width W4 of the contact area CA becomes smaller.

Therefore, in the micro heater 20 of the present embodiment, the widths W1 and W2 of the plurality of connecting portions 22, the length L1 of the second area A2 of the plurality of connecting portions, and the plurality of connecting portions 22 are shown. The loss of heat generated from the heating unit 21 may be reduced by adjusting the separation distance L2 and the width W4 of the contact area CA therebetween.

In detail, the length L1 of the second area A2 of the plurality of connecting parts 22 may be maximized or the width W1 of the plurality of connecting parts 22 may be limited to maintain the support of the heating part 21. , W2) and the contact area 45 may be minimized to reduce the loss of heat generated from the heating part 21. As a result, power consumed to drive the micro heater 20 can be reduced, and the applied power can be efficiently used for high temperature heating of the heating unit 21. In addition, the hot electron emission efficiency of the hot electron emission layer 30 applied to the heating unit 21 can be improved.

For example, as shown in FIG. 2, the width W2 of the second area A2 of the plurality of connection parts 22 is formed to be smaller than the width W3 of the heating part 21 so that the heating part ( The amount of heat transferred from 21 to the second area A2 of the plurality of connection parts 22 may be reduced. In addition, in order to reduce the loss of heat transferred from the plurality of connecting portions 22 to the plurality of supports 23, the width W4 of the contact area CA may be smaller than the width W1 of the first area. .

On the other hand, when the area of the contact area CA and the first area A1 of the plurality of connecting portions 22 corresponding to the contact area CA is too small, the support itself by the plurality of supports 23 is supported. Difficult to obtain structural stability. Therefore, the area of the contact area CA and the first area A1 should be greater than or equal to the minimum area capable of maintaining the support of the heating part 21 and the connecting part 22. do. As a result, as shown in FIG. 2, the widths W1 and W4 of the first area A1 and the contact area CA may be larger than the width W2 of the second area A2. .

3 is a cross-sectional view showing a hot electron emission apparatus according to another embodiment of the present invention. The same components as those shown in FIGS. 1A and 1B among the components shown in FIG. 3 are given the same reference numerals, and detailed description thereof will be omitted.

The substrate 10 and the micro heater 20 of the heat electron emission device 103 of this embodiment are the same as the substrate 10 and the micro heater 20 shown in FIGS. 1A and 1B. However, the thermal electron emission device 103 of the present embodiment further includes a charge preventing layer 40 formed on the substrate 10 and the plurality of supports 23. The charge preventing layer 40 prevents the hot electrons emitted from the hot electron emission layer 30 from being charged to the outside of the hot electron emission device.

When the substrate 10 is made of a glass material or plastic that is a non-conductor, hot electrons protruding from the hot electron emission layer 30 are filled in the substrate 10 or hot electrons are formed in a plurality of supports 23 made of a material having low conductivity. Can be charged. When the hot electrons are charged, a negative potential is formed at the bottom of the heating part 21 such that the hot electrons are impossible to be discharged to the upper portion of the hot electron emitting device 103 or the hot electrons are caused by a sudden discharge of the charged hot electrons. The release device 103 may become unstable. Therefore, in order to prevent the charging of the hot electrons, the hot electron emission device 103 may further include a charge preventing layer 40.

The charge preventing layer 40 may be made of a material having a specific resistance value of 10 ³ Ωcm ~ 10 ⁹ Ωcm. For example, the charge preventing layer 40 may be formed using amorphous silicon. The charge preventing layer 40 is applied to the top surface of the substrate 10 on which the hot electrons can be charged and the surfaces of the plurality of supports 23. Like the hot electron emission layer 30, the charge preventing layer 40 may be used in methods such as chemical vapor deposition, physical vapor deposition, electroplating, dipping, and the like. It can be formed by.

In the present embodiment, as shown in FIG. 1B, an example in which the charge preventing layer 40 is provided on the upper surface of the substrate 10 and the surfaces of the plurality of supports 23 is described. It may be provided on the front surface of the micro heater 20.

Meanwhile, the charge preventing layer 40 may be formed on the hot electron emission layer 30, and the hot electron emission layer 30 may be formed on the charge preventing layer 40.

4A is a perspective view illustrating a hot electron emission device according to still another embodiment of the present invention, and FIG. 4B is a cross-sectional view taken along the cutting line II-II ′ of FIG. 4A. 4A and 4B, the same components as those shown in FIGS. 1A, 1B, and 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.

4A and 4B, in the hot electron emission device 104 according to the present exemplary embodiment, two or more micro heaters 20 are arranged side by side on the substrate 10 to form a micro heater array. The hot electron emission layer 30 is formed on the micro heater 20 to enable the release of the hot electrons in the form of an array. In addition, a large area can be arranged by arranging a plurality of micro heaters side by side, thereby making it possible to easily implement a planar hot electron emission source having a large area.

In the present embodiment, the hot electron emission layer 30 and the charge preventing layer 40 are applied to both the heating part 21, the plurality of connecting parts 22, the surfaces of the plurality of supports 23, and the upper surface of the substrate 10. . When the hot electron emission layer 30 and the charge preventing layer 40 are formed by the immersion method, the hot electron emission layer 30 and the charge preventing layer 40 on the micro heater 20 and the substrate 10 can be quickly and easily. Can be formed.

In addition, the hot electron emission device 104 according to the present embodiment further includes a plurality of gates 50 for turning on / off the emission of hot electrons protruding from the hot electron emission material. The plurality of gates 50 are present on the substrate 10 to be orthogonal to the heating unit 10 at the lower portion of the heating unit 21, and spaced apart from the plurality of supports 23, respectively. In the present embodiment in which a plurality of micro heaters 20 are provided side by side, each gate 50 extends in a direction perpendicular to the length direction of the heating unit 21 to form a line shape crossing the plurality of heating units 21. Have

A voltage may be applied to both ends of the plurality of gates 50 to control the emission of hot electrons protruding from the hot electron emission layer 30. For example, when the voltage applied to the gate 50 is adjusted to a negative potential lower than the voltage applied to the heating unit 21, the hot electrons protruding from the hot electron emission layer 30 may be formed in the micro heater 20. The discharge to the top can be blocked. Accordingly, by controlling the voltage applied to each gate 50, the hot electron emission from the hot electron emission layer 30 corresponding to the region provided with the plurality of gates 50 may be turned on / off.

As such, the hot electron emission device 104 may be applied to an electronic device such as a transistor and a display by having an on / off function by the gate 50.

Meanwhile, since the plurality of gates 50 are provided on the upper surface of the substrate 10, when the substrate 10 is glass or plastic, hot electrons may be prevented from filling on the upper surface of the substrate 10. . As a result, the thermal electron emission device 104 including the gate 50 may omit the charge preventing layer 40.

5 is a cross-sectional view for explaining a method of checking whether or not the hot electron emission of the hot electron emission device of the present invention. Of the components shown in FIG. 5, the same reference numerals are used for the same components as those shown in FIGS. 1A and 1B, and detailed description thereof will be omitted.

Referring to FIG. 5, the phosphor substrate 200 is provided on the hot electron emission device 100. The phosphor substrate 200 includes a substrate 210 and a transparent electrode 220 and a phosphor layer 230 sequentially provided on the substrate 210. In the present embodiment, the transparent electrode 220 is made of indium tin oxide (ITO). The phosphor substrate 200 is provided on the hot electron emission device 100 such that the phosphor layer 230 faces the hot electron emission layer 30.

In the heat emission device 100 of the present embodiment, the hot electron emission layer 30 and the charge preventing layer 40 are sequentially provided on both the surface of the micro array 20 and the upper surface of the substrate 10.

When a voltage is applied to the heating unit 21, the hot electron emission layer 30 is heated by heat generated from the heating unit, and hot electrons are emitted from the hot electron emission 30 layer. In this case, when a voltage having a higher potential than that of the heating part 21 is applied to the transparent electrode 220, the emitted hot electrons move toward the phosphor substrate 200 so that the phosphor of the phosphor layer 230 emits light. do. Thus, whether or not the hot electron emission device 100 emits hot electrons may be easily determined through whether the phosphor layer 230 emits light.

6 is a photograph showing a hot electron emission state of the hot electron emission device according to an embodiment of the present invention.

In the present embodiment, two micro heaters were formed on the substrate, and a hot electron emission layer and a charge preventing layer were sequentially applied on the micro heater and the substrate to complete the hot electron emission apparatus. The micro heater of this embodiment is the same as the configuration of the micro heater shown in Figs. 1A and 1B, and the length of the heating portion is 15 mm, and the width of the heating portion is 10 um. In addition, the width of each of the plurality of connecting portions is formed to be 5um, the length of the second area A2 of each of the plurality of connecting portions is 40um, and the separation distance of the plurality of connecting portions is 100um.

The hot electron emission layer was formed by applying BaO, and the charge preventing layer was formed by applying amorphous silicon.

Thereafter, as described with reference to FIG. 5, the phosphor substrate on the top of the hot electron emission device was provided to check the hot electron emission state of the hot electron emission device.

As shown in FIG. 6, it can be observed that the phosphor emits light uniformly in the phosphor layer region corresponding to the micro heater. Through this, it can be seen that the hot electrons are uniformly emitted from the hot electron emission device. Since the heating part of the micro heater of the present invention has a uniform temperature distribution, it is possible to provide uniform energy to the hot electron emission layer. As a result, uniform hot electrons can be emitted in the entire region of the heating section.

In addition, by forming the hot electron emission layer from BaO having a small work function, a large amount of hot electrons can be uniformly released even under low driving power of the micro heater. In this embodiment, the power consumed for driving the micro heater is 0.15W.

In addition, the hot electrons may not be charged by the charge preventing layer and may be stably emitted.

On the other hand, when the hot electrons were emitted by applying 0.23W of driving power to each of the two micro heaters, a 0.3 mA emission current was measured from the hot electron emission device. As described above, when the thermo-electron emitting device of the present invention is used, a high emission current density of 0.3 mA can be obtained under low driving power.

7A to 7B are simulations showing the trajectories of the hot electrons emitted from the hot electron emitting device.

This embodiment shows the on / off function of the hot electron emission according to the applied voltage of the gate in the hot electron emission device having a gate. The structure of the hot electron emission device used in this embodiment is the same as that of the hot electron emission device shown in FIG. 4A. However, in the present embodiment, two micro heaters are provided on the substrate.

In addition, a phosphor substrate is provided on the hot electron emitting device, and hot electrons generated from the hot electron emitting device move to the phosphor substrate side.

In this embodiment, the voltage applied to the micro heater and the voltage applied to the transparent electrode on the phosphor substrate were fixed at 500 V and 0 V, respectively, and the voltage applied to the gate was adjusted to observe the trajectory of the hot electrons according to the voltage of the gate. On the other hand, the voltages are relative to each other.

FIG. 7A simulates a trajectory of hot electrons emitted when a voltage of +50 V is applied to a gate. As shown in FIG. 7A, when the voltage of the gate is + 50V, the hot electrons emitted from the hot electron emission layer spread widely and move to the phosphor layer. Through the trajectory of the hot electrons, it can be seen that the hot electrons are uniformly emitted under the gate voltage.

7B simulates a trajectory of hot electrons emitted when a voltage of 0 V is applied to the gate. As shown in FIG. 7B, when the voltage of the gate is 0 V, the number of hot electrons emitted from the hot electron emission layer is reduced than before, and the hot electrons emitted are overfocused and moved to the phosphor layer.

FIG. 7C simulates a trajectory of hot electrons emitted when a voltage of −35 V is applied to a gate. As shown in FIG. 7A, when the voltage of the gate is -35V, it can be seen that hot electrons moving from the hot electron emission layer to the phosphor layer are reduced more than before.

On the other hand, when the gate voltage is -50V, the emission of hot electrons is blocked.

As described above, the amount of hot electrons emitted from the hot electron emission layer and the trajectory of hot electrons vary according to the voltage applied to the gate. Therefore, the hot electron emission can be turned on / off in the hot electron emission device by adjusting the voltage applied to the gate.

FIG. 8A is a plan view illustrating a hot electron emission device according to yet another exemplary embodiment. FIG. 8B is a cross-sectional view taken along the line III-III ′ of FIG. 8A.

The same reference numerals for the same components as those shown in FIGS. 4A and 4B among the components illustrated in FIGS. 8A and 8B are denoted together, and detailed description thereof will be omitted.

8A and 8B, the hot electron emission device 105 of the present embodiment includes a substrate 10, a micro heater 20 ′, and a hot electron emission layer 35.

 The micro heater 20 'includes a heating part 21' and a plurality of supports 23 '. The heating part 21 ′ extends in one direction on the substrate 10. The plurality of supports 23 ′ are partially provided between the heating unit 21 ′ and the substrate 10, and the heating unit 21 ′ is disposed below the heating unit 21 ′. I support it. The plurality of supports 23 'are arranged to be spaced apart from each other along the longitudinal direction of the heating part 21'.

The heating portion 21 'is divided into a plurality of third regions A3 and a plurality of fourth regions A4, and each of the plurality of third regions A3 is the heating portion 21' and the plurality of portions. Of the plurality of fourth regions A4 exist between the plurality of third regions A3 respectively.

On the other hand, as in the micro heater 20 shown in Figs. 1A and 1B, in order to reduce the power consumed to drive the micro heater 20 'of the present embodiment, the plurality of supports 23' and the heating unit The area of the contact area CA of 21 'should be adjusted so as to reduce as much as possible the extent that the plurality of supports 23' maintain the support of the heating part 21 '. In addition, it is preferable that each width of the plurality of third regions A3 is greater than each width of the plurality of fourth regions A4. The reason for this is that in order to facilitate the etching of the plurality of supports 23 'and in particular the etching of the contact area CA, the respective widths of the plurality of third regions A3 may be defined by the plurality of fourth regions A4. This is because it needs to be larger than each width.

The hot electron emission layer 35 is applied to the upper surface of the substrate 10 and the surface of the micro heater 20 'and receives heat generated from the micro heater 20' to emit hot electrons. In the present embodiment, the hot electron emission layer 35 is made of a mixture of a hot electron emission material and a charge preventing material, and is formed in a single layer structure. When the hot electron emission layer 35 is heated by the heating unit 21 ′, hot electrons pop out of the hot electron emission material, and the hot electrons are filled in the substrate 10 or the plurality of supports 23 ′ by the charge preventing material. Can be prevented and emitted to the outside of the hot electron emitting device 105.

On the other hand, the hot electron emission layer 35 may be made of only the hot electron emission material.

In addition, as shown in FIG. 8A, two or more micro heaters 20 ′ may be arranged in parallel with each other to form a micro heater array, and as a result, an array type hot electron emission source may be realized.

The hot electron emission device 105 according to the present embodiment further includes a plurality of gates 50 for turning on / off the emission of hot electrons protruding from the hot electron emission material. The plurality of gates 50 are present on the substrate 10 to be orthogonal to the heating portion 21 'at each lower portion of the fourth regions A4 of the heating portion 21', and the plurality of supports 23 '. ) And spaced apart respectively. In the present exemplary embodiment in which a plurality of micro heaters 20 'are provided side by side, the plurality of gates 50 extend in a direction perpendicular to the longitudinal direction of the heating portion 21', respectively, so that the plurality of heating portions 21 'are provided. Traverse)

9A to 9E illustrate a process of manufacturing the hot electron emission device illustrated in FIG. 4B with respect to the side surfaces 9a, 9b, 9d, and 9e and the plane 9c.

Referring to FIG. 9A, a plurality of gates 50 are formed on the substrate 10 to turn on / off hot electron emission from the hot electron emission layer 30. The plurality of gates 50 are formed by applying a gate conductive film onto the substrate 10 and patterning the gate conductive film by photolithography or the like.

Next, as shown in FIG. 9B, the sacrificial layer 1 and the heating layer 2 are sequentially formed on the entire surface of the substrate 10.

Referring to FIG. 9C, the heating layer 2 is patterned into a heating part 21 and a plurality of connecting parts 22. The heating part 21 extends in one direction D1. The plurality of connection parts 22 are arranged to be spaced apart from each other along the longitudinal direction D1 of the heating part 21, and the plurality of connection parts 22 are disposed in the longitudinal direction D1 of the heating part 21 from both sides of the heating part 21. Each extends in the photographic direction D2.

Referring to FIG. 9D, the sacrificial layer 1 is lifted off by etching, and thus the sacrificial layer 1 has a plurality of supports 23. The sacrificial layer 1 is etched in an area except for the lower portion of the heating part 21 and the area in contact with the plurality of supports 23 of the plurality of connection parts 22. As a result, the heating part 21 is provided on the substrate 10 spaced apart from each other, and the plurality of supports 23 are partially provided under the plurality of connecting parts 22, and the plurality of gates 50 are provided. Is revealed.

Here, in order to reduce heat transfer between the plurality of connections 22 and the plurality of supports 23, the etching is performed such that the area of the contact area of the plurality of supports 23 and the plurality of connections 22 is reduced. Is performed.

Next, as shown in FIG. 9E, the micro-heater 20 includes a heat electron-emitting material that receives heat generated from the micro-heater 20 to emit hot electrons and a charge preventing material that prevents the emitted hot electrons from being charged. The thermal electron emission layer 30 and the charge preventing layer 40 are formed by coating on the surface of the substrate and the upper surface of the substrate 10.

In the present embodiment, after the micro heater 20 is formed, the hot electron emission material and the charge preventing material are respectively coated to form a double layer of the hot electron emission layer 30 and the charge preventing layer 40. A mixture of materials may be applied to the micro heater 20 and the substrate 10 to form a single layer.

Although the present invention has been described in connection with the above-mentioned embodiments, it is possible to make various modifications or variations without departing from the spirit and scope of the invention. Accordingly, the appended claims will cover such modifications and variations as fall within the spirit of the invention.

Figure 1a is a perspective view showing a hot electron emission device according to an embodiment of the present invention.

FIG. 1B is a cross-sectional view taken along the line II ′ of FIG. 1A.

2 is a plan view showing a hot electron emission apparatus according to another embodiment of the present invention.

3 is a cross-sectional view showing a hot electron emission apparatus according to another embodiment of the present invention.

Figure 4a is a perspective view showing a hot electron emission device according to another embodiment of the present invention.

4B is a cross-sectional view taken along the line II-II ′ of FIG. 4A.

6 is a photograph showing a hot electron emission state of the hot electron emission device according to an embodiment of the present invention.

7A to 7B are simulations showing the trajectories of the hot electrons emitted from the hot electron emitting device.

8A is a plan view illustrating a hot electron emission device according to still another embodiment of the present invention.

FIG. 8B is a cross-sectional view taken along the line III-III ′ of FIG. 8A.

9A to 9E illustrate a process of manufacturing the hot electron emission device illustrated in FIG. 4B with respect to the side surfaces 9a, 9b, 9d, and 9e and the plane 9c.

Claims (25)

Board; A micro heater provided on the substrate; And And a hot electron emission layer provided on the micro heater and receiving heat generated from the micro heater to emit hot electrons. The method of claim 1, wherein the micro heater, A heating part spaced apart from the substrate; And And a plurality of supports provided to support the heating unit and spaced apart from each other. The hot electron emission device of claim 2, wherein the hot electron emission layer is formed of a material having a work function smaller than the work function of the material forming the heating part. The hot electron emission device of claim 3, wherein the hot electron emission layer is partially formed in the heating unit. The method of claim 4, wherein The heating unit extends in one direction on the substrate, And the plurality of supports are partially provided between the heating unit and the substrate, and support the heating unit under the heating unit. The method of claim 4, wherein the micro heater, And a plurality of connection parts respectively extending from both sides of the heating part and spaced apart from each other along the longitudinal direction of the heating part. The method of claim 6, The plurality of supports are respectively provided in the lower portion of the plurality of connection portion hot electron emission device, characterized in that for supporting the heating unit. The method according to claim 5 or 7, And a charge preventing layer provided on the substrate and the plurality of supports to prevent the charging of hot electrons emitted from the hot electron emission layer. The device of claim 8, wherein the charge preventing layer is formed of a material having a specific resistance value of 10 ³ Ωcm to 10 ⁹ Ωcm. 8. The gate of claim 5, wherein the gate is disposed on the substrate so as to be orthogonal to the heating unit under the heating unit, spaced apart from the plurality of supports, respectively, and turns on / off hot electron emission of the hot electron emission layer. Hot electron emission device characterized in that it further comprises. 10. The apparatus of claim 9, wherein two or more micro heaters are arranged side by side with each other. 11. The apparatus of claim 10, wherein two or more micro heaters are arranged side by side with each other. Board; A micro heater provided on the substrate; And And a hot electron emission layer applied to the substrate and the micro heater and receiving heat generated from the micro heater to emit hot electrons. The method of claim 13, wherein the micro heater, A heating part spaced apart from the substrate; And And a plurality of supports provided to support the heating unit and spaced apart from each other. 15. The apparatus of claim 14, wherein the hot electron emission layer comprises a hot electron emission material and a charge preventing material. The hot electron emitting device of claim 15, wherein the hot electron emitting material has a work function smaller than a work function of a material forming the heating part. The method of claim 16, The charge preventing material is a heat electron emission device, characterized in that the material having a specific resistance value of 10 ³ Ωcm ~ 10 ⁹ Ωcm. The method of claim 17, The heating unit extends in one direction, And the plurality of supports are partially provided between the heating unit and the substrate, and support the heating unit under the heating unit. The method of claim 17, The micro heater further includes a plurality of connection parts extending from both sides of the heating part and arranged spaced apart from each other along the longitudinal direction of the heating part, The plurality of supports are provided on the lower portion of the plurality of connecting portions, respectively, characterized in that the support for the heating unit and the plurality of hot electron emission device. 20. The gate of claim 18 or 19, wherein the gate is disposed on the substrate so as to be orthogonal to the heating portion at the bottom of the heating portion, and is spaced apart from the plurality of supports, respectively, to turn on / off hot electron emission from the thermal electron emission material. Hot electron emission device characterized in that it further comprises. Forming a micro heater on the substrate; And And applying a hot electron emission material to the micro heater to receive the heat generated from the micro heater to emit hot electrons. The method of claim 21, wherein in the forming of the micro heater, The micro heater may include a heating unit spaced apart from the substrate; And And a plurality of supports provided to support the heating unit and spaced apart from each other. The method of claim 22, And applying a charge preventing material to the substrate and the plurality of supports to prevent the discharged hot electrons from being charged. The method of claim 23, wherein prior to forming the micro heater, Forming a plurality of gates on / off on the substrate to turn on / off hot electron emission from the hot electron emitting material, The plurality of gates are formed on the substrate to be orthogonal to the heating unit at the lower portion of the heating unit, characterized in that spaced apart from each other. Forming a micro heater on the substrate; And And applying a mixture of a hot electron emission material that receives heat generated from the micro heater to emit hot electrons and a charge preventing material that prevents the discharged hot electrons from being charged on the micro heater and the substrate. Method for manufacturing a hot electron emission device.

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