Field emission type emitter and method of manufacturing thereof

Abstract: The field emission type emitter comprises a conductive substrate (101), an insulating film (102) formed on the conductive substrate (101), a cavity (102a) formed in the insulating film (102), a cathode (103) formed on the conductive substrate (101) in the cavity (102a), and a gate electrode (105) formed over the insulating film (102). The gate electrode (105) is preferably made of refractory metal silicide. A polycrystalline silicon film (104) is preferably formed between the gate electrode (105) and the insulating film (102). The side walls of the insualating film in the portion of the cavity (102a) preferably have an inverse tapered shape. In the case where as glass substrate (201 in Fig. 5) is used, a conductive film (203) is formed on the glass substrate through an insulating film (202) and the cathode (205) is formed on the conductive film (203) in the cavity (204a). Low cost manufacturing methods of the field emission type emitter are also disclosed. The invention provides for the advantages that a stable structure of the cathode (103;205) and the gate electrode (105) are achieved such that large area field emission type emitter array flat panel displays can be produced with satisfying long time results.

Description: Field of the Invention The invention relates to a field emission type emitter and a method of manufacturing thereof which can be suitably applied to a flat pannel display such as a flat CRT. Description of the Prior Art Hitherto, as a field emission type emitter of the size of the micron order, a emitter called a Spindt type has been known. Its manufacturing method is as follows. As shown in Fig. 1A, after a silicon dioxide (SiO₂) film 2 was first formed onto a conductive silicon (Si) substrate 1 by a thermal oxidation method, a CVD method or a sputtering method, a molybdenum (Mo) film 3 is formed onto the SiO₂ film 2 by a sputtering method or an electron beam evaporation deposition method as a material to form a gate electrode. A thickness of the SiO₂ film 2 is about 1 to 1.5 µm. A thickness of the Mo film 3 is about 10⁻⁷ m (thousands Å), for example. After that, a resist pattern 4 having a shape corresponding to a gate electrode to be formed is formed onto the Mo film 3 by a lithography. Then, the resist pattern 4 is used as a mask and the Mo film 3 is etched by a wet etching method or a dry etching method, thereby forming a gate electrode 5 as shown in Fig. 1B. The gate electrode 5 has an opening 5a having, for example, a circular shape having a diameter of about 1 µm. Subsequently, the resist pattern 4 and the gate electrode 5 are used as masks and the SiO₂ film 2 is etched by a wet etching method, thereby forming a cavity 2a as shown in Fig. 1C. After the resist pattern 4 was removed, an oblique evaporation deposition is executed by an electron beam evaporation deposition method in a direction with a predetermined inclination angle to the substrate surface, thereby forming a peeling-off layer 6 made of, e.g., aluminum (Aℓ ) on the gate electrode 5 as shown in Fig. 1D. The oblique evaporation deposition is executed while the Si substrate 1 is rotated around its center. Then, Mo is evaporation deposited by an electron beam evaporation deposition method as a material to form a cathode in the direction perpendicular to the substrate surface. Due to this, as shown in Fig. 1E, a cathode 7 is formed on the Si substrate 1 in the cavity 2a. Reference numeral 8 denotes a Mo film formed on the peeling-off layer 6 at the time of the evaporation deposition. A thickness of the Mo film 8 is about 1 to 2 µm. After that, the peeling-off layer 6 is removed by a lift-off method together with the Mo film 8 formed thereon, thereby completing a target field emission type emitter as shown in Fig. 1F. Since it is necessary to execute the electron emission from the cathode 7 in the vacuum of about 10⁻⁶ Torr or less, the above field emission type emitter is actually sealed in the vacuum by opposite plates and other members (not shown). The above conventional field emission type emitter shown in Fig. 1F has the following many drawbacks. That is, since the above refractory metal such as Mo which is used as a material of the gate electrode 5 is likely to be oxidized, the gate electrode 5 is easily oxidized in the manufacturing process and an electric conductivity decreases. Thus, the electron emission from the cathode 7 cannot be stably performed. There is also a case where a deformation of the gate electrode 5 occurs due to the oxidation. Further, since an internal residual stress due to a film formation of the refractory metal such as Mo or the like is large, a deformation of the gate electrode 5 easily occurs. Consequently, the gate electrode 5 is easily peeled off from the SiO₂ film 2. Further, in the manufacturing method of the above conventional field emission type emitter, to actually execute the lift-off of the Mo film 8, it is necessary that an etchant solution for lift-off reaches the peeling-off layer 6 under the Mo film 8. However, as shown in Fig. 1E, the Mo film 8 covers the substrate surface almost completely, so that a thin portion of the Mo film 8 just over the cathode 7 is the only place where the etchant solution for lift-off can enter below the Mo film 8. Therefore, the etchant solution for lift-off is hard to reach the peeling-off layer 6, so that it is difficult to actually execute the lift-off. This problem takes a remarkable effect, especially in the case of forming a large area field emission type emitter array. That is, in the field emission type emitter array, the pitch of the cathode 7 is set to, e.g., about 10 µm, while the diameter of the opening 5a of the gate electrode 5 which is formed just over the cathode 7 is set to about 1 µm and is very small as compared with the pitch of the cathode 7. In this case, there is no place where the etchant solution for lift-off can enter below the Mo film 8. As a result, the lift-off could not be executed partly or the thin Mo film 8 was left on the peeling-off layer 6, and the lift-off could not be executed completely. In addition, even if the lift-off could be executed completely, the lift-off took a fairly long time and the productivity was low. Further, since the conventional field emission type emitter shown in Fig. 1F mentioned above has an overhanging structure in which the gate electrode 5 is projected to the inside of the cavity 2a in parallel with the substrate surface, there are problems such that the gate electrode 5 is weak in terms of structure and a peel-off or the like from the SiO₂ film 2 is likely to occur. On the other hand, a field emission type emitter of a structure as shown in Fig. 2 has also been known. As shown in Fig. 2, in the field emission type emitter, the side walls of a cavity 12a formed in an SiO₂ film 12 are perpendicular to the substrate surface. Such a cavity 12a is formed by a reactive ion etching (RIE) method. Reference numerals 11, 13, and 14 denote a Si substrate, a cathode and a gate electrode, respectively. The conventional field emission type emitter shown in Fig. 2 has a structure such that the whole gate electrode 14 is supported by the SiO₂ film 12, so that the gate electrode 14 is strong in terms of structure. In this case, however, there are the following problems. That is, in the case of actually forming the cavity 12a by an RIE method, it is not always easy to control the shape of the bottom portion because a diameter of cavity 12a is small. Therefore, there is a case where the side walls of the cavity 12a are not always perpendicular to the substrate surface and a diameter of bottom portion is small. In such a case, there are fears such that a defective shape of the cathode 13 which is formed in the cavity 12a occurs and a defective insulation between the cathode 13 and the gate electrode 14 occurs. OBJECTS AND SUMMARY OF THE INVENTION It is therefore the primary object of the present invention to provide a field emission type emitter which can stably emit electrons from a cathode and prevent a deformation of a gate electrode due to oxidation and the like and a method of manufacturing such a field emission type emitter. The above object is according to the invention solved by the features of claim 1. Depending claims 2 to 4 each specify advantageous developments thereof. Independent claim 5 specifies a manufactoring method solving the above object, and claims 6 and 7 depending therefrom specify advantageous developments thereof. The above, and other objects, features and advantages of the present invention will become readily apparent from the following detailed description thereof which is to be read in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Figs. 1A to 1F are cross sectional views for explaining a manufacturing method of the conventional field emission type emitter; Fig. 2 is a cross sectional view showing another conventional field emission type emitter; Fig. 3 is a cross sectional view showing a field emission type emitter according to the first embodiment of the invention; Figs. 4A to 4D are cross sectional views for explaining a manufacturing method of the field emission type emitter shown in Fig. 3; Fig. 5 is a cross sectional view showing a field emission type emitter according to the second embodiment of the invention; Figs. 6A to 6D are cross sectional views for explaining a manufacturing method of the field emission type emitter shown in Fig. 5; Fig. 7 is a perspective view showing the third embodiment of the invention in which line-shaped conductive films formed on a glass substrate and an arrangement example of cathodes formed on the conductive films are shown; Fig. 8 is a cross sectional view showing a field emission type emitter according to the fourth embodiment of the invention; Fig. 9 is a cross sectional view showing a field emission type emitter according to the fifth embodiment of the invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the invention will be described hereinbelow with reference to the drawings. As shown in Fig. 3, in a field emission type emitter according to the first embodiment, an insulating film 102 such as an SiO₂ film having a film thickness of about 1 µm is formed on a conductive substrate 101 such as an Si substrate in which impurities of, e.g., the n type or p type have been doped at a high concentration. A cavity 102a having, for instance, a circular flat shape is formed in the insulating film 102. A conical cathode 103 having a pointed tip and made of metal such as Mo, tungsten (W), or the like having a high melting point and a low work function is formed on the conductive substrate 101 in the cavity 102a. A gate electrode 105 made of refractory metal silicide such tungsten silicide as (WSi x ) is formed over the insulating film 102 around the cavity 102a through a polycrystalline Si film 104 so as to surround the cathode 103. A thickness of polycrystalline Si film 104 is set to a value within a range, e.g., about from 500 to 1000 Å . A thickness of refractory metal silicide film such as a WSi x film which forms the gate electrode 105 is set to a value within a range from 0.2 to 0.5 µm. An Si composition ratio x of WSi x is preferably selected to a value within a range from 2.4 to 2.8. When x lies within the above range, an internal residual stress upon formation of the WSi x film is minimum. Further, if x > 2, SiO₂ is easily formed when WSi x is oxidized, so that the oxidation of W is effectively suppressed. A diameter of opening portion of the gate electrode 105 just over the cathode 103 is set to, e.g., about 1 µm. By arranging the cavities 102a and cathodes 103 of the numbers corresponding to the application onto the same conductive substrate 101, a field emission type emitter array can be constructed. In the field emission type emitter according to the first embodiment, in a manner similar to the conventional field emission type emitter which has already been mentioned, by applying an electric field of about 10⁶ V/cm or more between the gate electrode 105 and the cathode 103, the electron emission can be performed without heating the cathode 103 and it is sufficient to set a gate voltage to a value within a range about from tens to 100 V. Since the electron emission from the cathode 103 needs to be executed in the vacuum of about 10⁻⁶ Torr or less, the field emission type emitter according to the first embodiment is actually sealed in the vacuum by opposite plates and other members (not shown). A manufacturing method of the field emission type emitter according to the first embodiment constructed as mentioned above will now be described. As shown in Fig. 4A, the insulating film 102 is first formed on the conductive substrate 101 by, for instance, a CVD method. Then, the polycrystalline Si film 104 and a refractory metal silicide film 106 such as a WSi x film are sequentially formed on the insulating film 102 by the CVD method. A resist pattern 107 having a shape corresponding to a gate electrode to be formed is subsequently formed onto the refractory metal silicide film 106 by a lithography. The resist pattern 107 is used as a mask and the refractory metal silicide film 106 and the polycrystalline Si film 104 are sequentially etched by a wet etching method or a dry etching method. Thus, as shown in Fig. 4B, the gate electrode 105 is formed and the polycrystalline Si film 104 is patterned so as to have the same shape as that of the gate electrode 105. Subsequently, the resist pattern 107, gate electrode 105, and polycrystalline Si film 104 are used as masks and the insulating film 102 is etched by a wet etching method using an etchant of, for example, the hydrofluoric acid system, thereby forming the cavity 102a as shown in Fig. 4C. The wet etching can be also executed after the resist pattern 107 was removed. After the resist pattern 107 was removed, as shown in Fig. 4D, by obliquely executing an evaporation deposition to the substrate surface in an oblique direction, a peeling-off layer 108 made of, e.g., Aℓ or nickel (Ni) is formed on the gate electrode 105. After that, for instance, Mo, W, or the like is evaporation deposited as a material to form a cathode in the direction perpendicular to the substrate surface. Thus, the cathode 103 is formed on the conductive substrate 101 in the cavity 102a. Reference numeral 109 denotes a metal film which has been evaporation deposited onto the peeling-off layer 108. The peeling-off layer 108 is then removed by a lift-off method together with a metal film 109 formed on the peeling-off layer 108, thereby completing a target field emission type emitter as shown in Fig. 3. As mentioned above, according to the first embodiment, since the gate electrode 105 is made of refractory metal silicide such as WSi x , the gate electrode 105 is not oxidized in the manufacturing processes. Therefore, the reduction of the electric conductivity of the gate electrode 105 by the oxidation can be prevented. Consequently, electrons can be stably emitted from the cathode 103. The deformation of the gate electrode 105 by the oxidation can be also prevented. Moreover, since refractory metal silicide as a material of the gate electrode 105 is formed by the CVD method, the internal residual stress of the gate electrode 105 can be reduced by controlling the Si composition ratio x of refractory metal silicide. Thus, the deformation of the gate electrode 105 can be also prevented by such a decrease in internal residual stress. Further, since the polycrystalline Si film 104 is formed between the gate electrode 105 and the insulating film 102, an adhesive performance of the gate electrode 102 to the underlayer can be improved. Thus, it is possible to effectively prevent that the gate electrode 105 is peeled off from the underlayer due to the deformation. Since refractory metal silicide such as WSi x as a material of the gate electrode 105 is chemically stable and has a good chemical resistance, it is convenient on manufacturing. The field emission type emitter according to the first embodiment is suitable for use in, for instance, a flat CRT. As the conductive substrate 101 in the first embodiment, for instance, it is also possible to use a substrate which is obtained by forming a conductive film made of metal such as chromium (Cr) or Aℓ onto an insulating substrate such as glass substrate or ceramics substrate by a whole surface or in a line shape. In the first embodiment, the cavity 102a has been formed by the wet etching method. The cavity 102a, however, can be also formed by an anisotropic etching method such as an RIE method. In the case of using the anisotropic etching method, the cavity 102a having side walls which are almost perpendicular to the substrate surface is formed. Further, refractory metal silicide as a material forming the gate electrode 105 can be also formed by, for example, a sputtering method. Fig. 5 shows a field emission type emitter according to the second embodiment of the invention. As shown in Fig. 5, in the field emission type emitter according to the second embodiment, an insulating film 202 such as SiO₂ film or SiN x film is formed on a glass substrate 201. A line-shaped conductive film (cathode line) 203 made of metal such as Cr, Aℓ , or the like is formed on the insulating film 202. Reference numeral 204 denotes an insulating film such as an SiO₂ film having a thickness of about 1 µm. A cavity 204a having, for example, a circular flat plane shape is formed in the insulating film 204. A conical cathode 205 having a pointed tip and made of metal such as Mo, W, or the like having a high melting point and a low work functions is formed on the conductive film 203 in the cavity 204a. A gate electrode 207 made of refractory metal silicide such as tungsten silicide (WSi x ) or molybdenum silicide (MoSi x ) is formed over the insulating film 204 around the cavity 204a through a polycrystalline Si film 206 so as to surround the cathode 205. A thickness of polycrystalline film 206 is set to a value within a range, e.g., about from 500 to 1000 Å . A thickness of refractory metal silicide film such as a WSi x film which forms the gate electrode 207 is set to a value within a range, e.g., from 0.2 to 0.5 µm. A Si composition ratio x of WSi x is preferably selected to a value within a range, e.g., from 2.4 to 2.8. When a value of x lies within such a range, the internal residual stress upon formation of the WSi x film is minimum. Further, if x > 2, SiO₂ is likely to be formed when WSi x is oxidized, so that the oxidation of W is effectively suppressed. A diameter of an opening portion of each of the gate electrode 207 and the polycrystalline film 206 just over the cathode 205 is set to, e.g., about 1 µm. In the field emission type emitter according to the second embodiment, in a manner similar to the conventional field emission type emitter which has already been mentioned, by applying an electric field of about 10⁶ V/cm or more between the gate electrode 207 and the cathode 205, the electrons can be emitted without heating the cathode 205. It is sufficient to set a gate voltage to a value within a range about from tens to 100 V. Since it is necessary to perform the electron emission from the cathode 205 in the vacuum of about 10⁻⁶ Torr or less, the field emission type emitter according to the second embodiment is actually sealed in the vacuum by opposite plates and other members (not shown). A method of manufacturing the field emission type emitter according to the second embodiment constructed as mentioned above will now be described. As shown in Fig. 6A, the insulating film 202 is first formed onto the glass substrate 201 by, e.g., a CVD method. After that, a conductive film such as a metal film is formed onto the insulating film 202 by, for instance, a sputtering method. The conductive film is patterned in a predetermined shape and the conductive film 203 of a line shape is formed. Subsequently, the insulating film 204, polycrystalline film 206 and a refractory metal silicide film 208 such as a WSi x film are sequentially formed onto the whole surface of the conductive film 203 by, e.g., the CVD method. A resist pattern 209 having a shape corresponding to a gate electrode to be formed is formed onto the refractory metal silicide film 208 by a lithography. Then, the resist pattern 209 is used as a mask and the refractory metal silicide film 208 and polycrystalline Si film 206 are sequentially etched by a wet etching method or a dry etching method. Due to this, as shown in Fig. 6B, the gate electrode 207 is formed and the polycrystalline Si film 206 is patterned into the same shape as that of the gate electrode 207. The resist pattern 209, gate electrode 207, and polycrystalline Si film 206 are used as masks and the insulating film 204 is etched by a wet etching method using an etchant of, for example, the hydrofluoric acid system, thereby forming the cavity 204a as shown in Fig. 6C. The wet etching can be also executed after the resist pattern 209 was removed. After the resist pattern 209 was removed, as shown in Fig. 6D, an oblique evaporation deposition is executed in an oblique direction to the substrate surface, thereby forming a peeling-off layer 210 made of, e.g., Aℓ or Ni onto the gate electrode 207. After that, for instance, Mo, W, or the like is evaporation deposited as a material to form a cathode in the direction perpendicular to the substrate surface. Thus, the cathode 205 is formed onto the conductive film 203 in the cavity 204a. Reference numeral 211 denotes a metal film which has been evaporation deposited onto the peeling-off layer 210. After that, the peeling-off layer 210 is removed by a lift-off method together with the metal film 211 formed on the peeling-off layer 210, thereby completing a target field emission type emitter as shown in Fig. 5. As mentioned above, according to the second embodiment, there is used the glass substrate 201 which is cheaper than the Si substrate and in which a danger of the occurrence of a crack or a warp is small and a large area can be easily obtained. Therefore, the manufacturing costs of the field emission type emitter can be reduced. A manufacturing yield of the field emission type emitter can be improved because a danger such that a warp or a crack of the substrate occurs is small. Moreover, it is also possible to easily realize a large area of a flat pannel display such as a flat CRT by a field emission type emitter array. Further, the problem of the instability of the electron emission from the cathode 205 due to an unstable potential of the surface of the glass substrate 201 can be solved by forming the insulating film 202 onto the glass substrate 201 and by forming the cathode 205 over the insulating film 202 through the conductive film 203. According to the second embodiment, since the gate electrode 207 has been made of refractory metal silicide such as WSi x which is hardly oxidized, the gate electrode 207 is not oxidized in the manufacturing processes. Thus, a decrease in electric conductivity of the gate electrode 207 due to the oxidation can be prevented. Consequently, the electron emission from the cathode 205 can be stably executed. The deformation of the gate electrode 207 due to the oxidation can be prevented. Since refractory metal silicide as a material of the gate electrode 207 has been formed by the CVD method, the internal residual stress of the gate electrode 207 can be reduced by controlling the Si composition ratio x of refractory metal silicide. Thus, the deformation of the gate electrode 207 can be also prevented by such a decrease in internal residual stress. Further, since the polycrystalline Si film 206 has been formed between the gate electrode 207 and the insulating film 204, the adhesive performance of the gate electrode 207 to the underlayer can be improved. Thus, it is possible to effectively prevent that the gate electrode 207 is peeled off from the underlayer due to the deformation. Since refractory metal silicide such as WSi x is chemically stable and has a good chemical resistance, it is convenient on manufacturing. The field emission type emitter according to the second embodiment is suitable for use in, e.g., a flat CRT of a large area. Fig. 7 shows the third embodiment of the invention. As shown in Fig. 7, in the third embodiment, by forming a plurality of line-shaped conductive films 203 in parallel with each other and by arranging plurality of cathodes 205 onto each of the conductive films 203 in a straight line, the cathodes 205 can be driven every conductive film 203. Fig. 8 shows a field emission type emitter according to the fourth embodiment of the invention. As shown in Fig. 8, the field emission type emitter according to the fourth embodiment has a construction similar to the field emission type emitter according to the second embodiment except that the conductive film 403 is formed on the whole surface of the insulating film 402. According to the fourth embodiment, advantages owing to the use of the glass substrate 401 as mentioned in the second embodiment can be obtained. Although the cavity in the second and fourth embodiments has been formed by the wet etching method, the cavity can be also formed by an anisotropic etching method such as an RIE method. In the case of using the anisotropic etching method, the cavity having side walls which are almost perpendicular to the substrate surface is formed. Further, in the second and fourth embodiments, refractory metal silicide as a material which forms the gate electrode can be also formed by, for instance, a sputtering method or an evaporation deposition method. Fig. 9 shows a field emission type emitter according to the fifth embodiment of the invention. As shown in Fig, 9, in the fifth embodiment, the gate electrode 604 made of refractory metal silicide such as WSi x or MoSi x is formed on the insulating film 602 around the cavity 602a through a polycrystalline Si film 609 so as to surround the cathode 603. A thickness of polycrystalline Si film 609 is set to a value within a range, e.g., about from 500 to 1000 Å. A thickness of refractory metal silicide film such as a WSi x film which forms the gate electrode 604 is set to a value within a range, e.g., from 0.2 to 0.5 µm. An Si composition ratio x of WSi x is preferably selected to a value within a range, e.g., from 2.4 to 2.8. When a value of x lies within the above range, the internal residual stress upon formation of the WSi x film is minimum. Further, if x > 2, SiO₂ is likely to be formed when WSi x is subjected to the oxidation, so that the oxidation of W is effectively suppressed. As shown in Fig. 9, in the field emission type emitter according to the fifth embodiment, an insulating film 602 such as an SiO₂ film having a thickness of about 1 µm is formed on a conductive substrate 601 such as an Si substrate in which impurities of, e.g., n type or p type have been doped at a high concentration. A cavity 602a having, for instance, a circular flat plane shape is formed in the insulating film 602. In the fifth embodiment, the side walls of the insulating film 602 in the portion of the cavity 602a have an inverse tapered shape. That is, a diameter of bottom portion of the cavity 602a is larger than a diameter of the upper portion. A conical cathode 603 having a pointed tip and made of metal such as Mo, W, or the like having a high melting point and a low work function is formed on the conductive substrate 601 in the cavity 602a. The gate electrode 604 is formed on the insulating film 602 around the cavity 602a so as to surround the cathode 603. A diameter of the opening portion of the gate electrode 604 just over the cathode 603 is set to, e.g., about 1 µm. A field emission type emitter array can be constructed by arranging the cavities 602a and the cathodes 603 of the numbers corresponding to the application onto the same conductive substrate 601. In a manner similar to the conventional field emission type emitter which has already been mentioned, by applying an electric field of about 10⁶ V/cm or more between the gate electrode 604 and the cathode 503, the field emission type emitter according to the fifth embodiment can emit electrons without heating the cathode 603. It is sufficient to set a gate voltage to a value within a range about from tens to 100 V. Since it is necessary to perform the electron emission from the cathode 603 in the vacuum of about 10⁻⁶ Torr or less, the field emission type emitter according to the fifth embodiment is actually sealed in the vacuum by opposite plates and other members (not shown). The manufacturing method of the field emission type emitter according to the fifth embodiment provides the polycrystalline Si film 609 and a refractory metal silicide film as a conductive film to form a gate electrode which are sequentially formed onto the insulating film 602 by, e.g., a CVD method, and, after that, the resist pattern 606 is formed on them. According to the fifth embodiment, there are following advantages. That is, since the gate electrode 604 is made of refractory metal silicide, the gate electrode 604 is not oxidized in the manufacturing processes, so that a deterioration in electric conductivity of the gate electrode 604 due to the oxidation can be prevented. Thus, the electron emission from the cathode 603 can be stably performed. A deformation of the gate electrode 604 due to the oxidation can be prevented. Moreover, since refractory metal silicide as a material of the gate electrode 604 has been formed by a CVD method, the internal residual stress of the gate electrode 604 can be reduced by controlling the Si composition ratio x. Therefore, the deformation of the gate electrode 604 can be also prevented by the reduced internal residual stress. Further, since the polycrystalline Si film 609 is formed between the gate electrode 604 and the insulating film 602, an adhesive performance of the gate electrode 604 to the underlayer can be improved. Due to this, it is possible to effectively prevent that the gate electrode 604 is peeled off from the underlayer due to the deformation. Since refractory metal silicide such as WSi x as a material of the gate electrode 604 is chemically stable and has a good chemical resistance, it is convenient on manufacturing.

Claims: A field emission type emitter comprising: a conductive substrate (101); an insulating film (102) formed on the conductive substrate (101); a cavity (102a) formed in the insulating film (102); a cathode (103) formed on the conductive substrate (101) in the cavity (102a); and a gate electrode (105) formed over the insulating film (102), the emitter being characterized in that the gate electrode (105) is made of refractory metal silicide. A field emission type emitter according to claim 1, wherein a polycrystalline silicon film is formed between the insulating film (102) and the gate electrode (105). A field emission type emitter according to claim 1, wherein the conductive substrate (101) is formed of a conductive film (203) provided on a first insulating film (202) disposed on a glass substrate (201). A field emission type emitter according to claim 1, wherein the side walls of the insulating film (102) in the portion of the cavity (102a) have an inversed tapered shape. A method of manufacturing a field emission type emitter in accordance with claim 1, comprising following steps: sequentially forming the insulating film (102) on the conductive substrate (101) and then the poly-cristalline Si-film (104) and the refractory metal silicide film (106) on said insulating film (102); forming a resist pattern (107) having a shape corresponding to a gate electrode to be formed on the refractory metal silicide film (106); etching the refractory metal silicide film (106) and the polycristalline Si-film (104) sequentially and using the resist pattern (107) as an etching mask; forming the gate-electrode (105) and patterning the polycristalline Si-film (104) to have the same shape as that of the gate electrode (105); forming the cavity (102a) by etching the insulating film (102) and using at least the gate electrode (105) and the poly-cristalline Si-film (104) as etching mask; removing the resist pattern (107); forming a peeling-off layer (108) on the gate electrode (105) by obliquely executing an evaporation deposition to the substrate surface in an oblique direction; evaporation depositing a cathode material on the conductive substrate (101) in the cavity (102a) to form a cathode in the direction perpendicular to the substrate surface and a metal film onto the peeling-off layer (108); and removing the peeling-off layer (108) by a lift-off method together with a metal film (109) formed on the peeling-off layer (108). The method of manufacturing a field emission type emitter according to claim 5, wherein the etching step for etching the insulating film (102) conprises a wet etching using an etchant of, e.g. hydrofluoric acid system. The method of manufacturing a field emission type emitter in accordance with claim 5, wherein the step of etching the insulating film (102) is carried out by an anisotropic etching method, such as reactive ion etching (RIE) method.

Inventors: HASEGAWA TOSHIAKI, ISHIMARU TOSHIYUKI, KOMATSU HIROSHI, WATANABE HIDETOSHI, HASEGAWA, TOSHIAKI, ISHIMARU, TOSHIYUKI, KOMATSU, HIROSHI, WATANABE, HIDETOSHI
Applicants: SONY CORP, SONY CORPORATION
Application year: 1991
Main classification: H01J1
IPC codes: H01J9, H01J1