JP2009016233A - Manufacturing method of field emission type electron source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method capable of obtaining a field emission type electron source having good electron emission characteristics and a long life without requiring an annealing treatment.
The manufacturing method includes an ion implantation step of implanting carbon ions 40 at least at the tip of the emitter 18 after forming the emitter 18 mainly composed of silicon. The coordinates of the points P _{1 to} P ₆ on the orthogonal coordinates with the energy (unit: keV) of the carbon ion 40 as one axis and the implantation amount (unit: × 10 ¹⁷ ions / cm ² ) as the other axis are (energy , Injection amount), P ₁ (5,0.8), P ₂ (5,1.5), P ₃ (10,2.5), P ₄ (15,3.0), P ₅ (15, 2.0) and P ₆ (10, 1.6) are implanted with carbon ions 40 under conditions that are within a range surrounded by a straight line.
[Selection] Figure 4

Description

  The present invention relates to, for example, a field emission electron used for an ion beam space charge neutralization device, a field emission display, a light source (field emission lamp), an electron source used in an environment where high environmental resistance is required, and the like. The present invention relates to a method for manufacturing a source.

  An example of a method for manufacturing this type of field emission electron source is described in Patent Document 1.

  In this conventional manufacturing method, carbon ions are implanted into the surface of an emitter constituting a field emission electron source, and then annealed at a temperature of 300 ° C. to 1200 ° C. for several hours, thereby making the surface of the emitter have a low work function SiC. It is what turns into a layer. Thereby, it is said that good electron emission characteristics can be obtained. However, Patent Document 1 does not describe any implantation conditions such as carbon ion energy and implantation amount.

Japanese Patent Laid-Open No. 5-242796 (paragraphs 0016-0017, FIG. 1)

  In the above conventional manufacturing method, in order to obtain good electron emission characteristics, an annealing process is required in which annealing is performed at a temperature of 300 ° C. to 1200 ° C. for several hours after carbon ions are implanted into the emitter surface. As a result, the number of processes increases, and there is a problem that it takes time and cost to manufacture.

  Therefore, the main object of the present invention is to provide a manufacturing method capable of obtaining a field emission electron source having good electron emission characteristics and a long life without requiring annealing.

One of the manufacturing methods according to the present invention is a method of manufacturing a field emission electron source having a pointed tip and an emitter mainly composed of silicon, wherein at least the tip of the emitter is formed after the emitter is formed. An ion implantation step of implanting carbon ions, and in the ion implantation step, the carbon ion energy (unit is keV) is set on one axis, and the carbon ion implantation amount (unit is × 10 ¹⁷ ions / When the coordinates of the points P _{1 to} P ₆ on the orthogonal coordinates with the other axis as cm ² ) are represented by (energy, injection amount), P ₁ (5,0.8), P ₂ (5,1. 5), 6 points of P ₃ (10,2.5), P ₄ (15,3.0), P ₅ (15,2.0) and P ₆ (10,1.6) are connected with a straight line. In the range surrounded by (including straight line, the same applies below) It is characterized by implanting ions.

  According to the above manufacturing method, it can be confirmed by experiments and simulations that a field emission electron source having good electron emission characteristics and a long life can be obtained without performing annealing treatment after the ion implantation step. It was.

  The annealing treatment may not be performed because the carbon atoms implanted into the surface layer of the emitter under the above implantation conditions are interposed around the silicon atoms constituting the emitter, thereby making the emitter mainly composed of silicon. However, it is considered that the material has a metal-like electric conduction rather than a semiconductor, and therefore, good electron emission characteristics can be expressed without annealing.

  The lifetime of the electron emission could be extended because the carbon atom concentration distribution in the surface layer of the emitter due to the carbon ions implanted under the above implantation conditions was combined with the silicon atoms constituting the emitter, and the oxidation of silicon. This is because the distribution is effective in suppressing the above.

In the ion implantation step, P ₁ (5,0.8), P ₂ (5,1.5), P ₃ (10,2.5), P ₄ (12,2.7), P ₅ (12 , 1.7) and P ₆ (10, 1.6) may be implanted with carbon ions under conditions within a range surrounded by a straight line.

Another aspect of the manufacturing method according to the present invention is a method for manufacturing a field emission electron source having a pointed tip and an emitter mainly composed of silicon, wherein at least the tip of the emitter is formed after the emitter is formed. An ion implantation step of implanting carbon ions into the plasma, and a plasma treatment step of irradiating at least a tip of the emitter with plasma generated using a gas containing carbon after the ion implantation step, and In the ion implantation step, the point P ₁ on the orthogonal coordinates with the carbon ion energy (unit is keV) as one axis and the carbon ion implantation amount (unit is × 10 ¹⁷ ions / cm ² ) as the other axis. coordinates (energy, implantation dose) of to P ₆ expressed _{respectively, P 1 (5,0.8), P} 2 (5,1.5), P 3 (10,2.5), P 4 ( 15, 2.0), it is characterized by implanting carbon ions under the conditions in the range surrounded by the straight line connecting the two adjacent six points P ₅ (15,1.5) and P ₆ (10,1.0) .

  According to the above manufacturing method, it is possible to confirm by experiments and simulations that a field emission electron source having good electron emission characteristics and a longer life can be obtained without performing annealing treatment after the ion implantation step. did it.

  The reason why the lifetime of electron emission is further extended by adding the plasma treatment step is that a carbon-based film is formed on the surface of the emitter, and this serves to suppress oxidation of the emitter surface.

In the ion implantation step, P ₁ (5,0.8), P ₂ (5,1.5), P ₃ (10,2.5), P ₄ (12,2.7), P ₅ (12 , 1.2) and P ₆ (10, 1.0) may be implanted with carbon ions under conditions within a range surrounded by a straight line.

  Negative carbon ions may be used as carbon ions in the ion implantation step.

  According to the first aspect of the present invention, a field emission electron source having good electron emission characteristics and a long lifetime can be obtained without performing an annealing treatment after the ion implantation step. As a result, the annealing process can be omitted, and the number of processes and the manufacturing cost can be reduced.

  According to invention of Claim 2, in addition to the effect similar to the effect of invention of Claim 1, there exists the following further effect. That is, since the upper limit value of the carbon ion energy is made smaller than in the first aspect of the invention, carbon atoms caused by ion implantation are prevented from entering too deep inside the emitter, The carbon atom concentration distribution can be more effectively distributed to suppress oxidation of silicon constituting the emitter.

  According to invention of Claim 3, in addition to the effect similar to the effect of Claim 1, there exists the following further effect. That is, by adding a plasma treatment process, a carbon-based film is formed on the surface of the emitter, which functions to suppress oxidation of the emitter surface, so that the lifetime of electron emission can be further extended. That is, a field emission type electron source having a longer life can be obtained.

  According to invention of Claim 4, in addition to the effect similar to the effect of Claim 3, there exists the following further effect. That is, since the upper limit value of the carbon ion energy is made smaller than that of the invention described in claim 3, carbon atoms caused by ion implantation are prevented from entering too deep into the emitter, and within the surface layer portion of the emitter. The carbon atom concentration distribution can be more effectively distributed to suppress oxidation of silicon constituting the emitter.

  According to invention of Claim 5, there exists the following further effect. That is, since carbon ions are negative carbon ions, even if ion implantation is performed on an electrically floating electrode such as a gate electrode at the same time as ion implantation into the emitter, the charge of the electrode is charged with positive ions. Compared to the case of injection, it can be suppressed to be small. Therefore, since it is not necessary to suppress charging by connecting a lead wire to the electrode, the manufacturing method can be simplified. In addition, when producing carbon ions, negative ions can be produced more easily and in large quantities than positive ions, so that it becomes easy to realize the implantation amount as described above.

  FIG. 1 is an enlarged schematic plan view showing an example of a field emission electron source. FIG. 2 is an enlarged cross-sectional view showing one emitter around the field emission electron source shown in FIG.

  This field emission electron source 10 is also called a field emission electron source array (abbreviated as FEA), and has a large number (for example, about 1000 to 5000) of emitters 18. However, the number of emitters 18 is not limited to this, and may be one or more. The arrangement of the emitters 18 is also arbitrary.

  The field emission electron source 10 has a conductive cathode substrate 16 and a large number of sharply formed tips formed on the surface of the cathode substrate 16 as shown in FIG. A small emitter 18, a gate electrode (also referred to as an extraction electrode) 22 common to each emitter 18 that surrounds the vicinity of the tip of each emitter 18 with a small gap 26, and the gate electrode 22 and the cathode substrate 16 And an insulating layer 20 that is provided between the two and insulates the two. The cathode substrate 16 and each emitter 18 are electrically connected to each other.

  The cathode substrate 16 is made of a material mainly composed of silicon, for example. That is, the cathode substrate 16 may be a silicon substrate or a substrate in which impurities such as boron (B), phosphorus (P), arsenic (As), and antimony (Sb) are contained in the silicon substrate. The cathode substrate 16 may be made of another conductive material such as a metal. Alternatively, a conductive film (layer) mainly composed of silicon, for example, may be formed on the surface of an insulating substrate so that only the surface layer portion has conductivity.

  Each emitter 18 has a sharp pointed tip. In other words, the tip has a sharper shape. The example shown in FIG. 2 has a conical shape, but may have a pyramid shape or the like.

  Each emitter 18 is made of a material whose main component is silicon. For example, it may be made of only silicon, or silicon may contain impurities such as boron, phosphorus, arsenic, and antimony. Each emitter 18 may be formed integrally with the cathode substrate 16 on the surface of the cathode substrate 16 as in the example shown in FIG. In any case, the cathode substrate 16 and each emitter 18 are in an electrically conductive state.

  The gate electrode 22 has a small small hole 24 at a position corresponding to each emitter 18. Each small hole 24 has, for example, a circular shape, and the vicinity of the tip of each emitter 18 is located at the center of each small hole 24 with a small gap 26 between the inner wall of the small hole 24. .

The insulating layer 20 is made of, for example, silicon dioxide (SiO ₂ ), but may be made of other insulating materials.

  Between the cathode substrate 16 (in other words, each emitter 18 in conduction with the cathode substrate 16) and the gate electrode 22, the gate electrode 22 is set to the positive electrode side (in other words, each emitter 18 is set to the negative electrode side). For example, when a DC voltage of about 50V to 100V is applied, the electric field concentrates at the tip of each emitter 18, and electrons 12 are emitted from the tip of each emitter 18 by the field emission (field emission) phenomenon.

  An example of a method for manufacturing the field emission electron source 10 as described above will be described with reference to FIGS.

  First, the cathode substrate 16 is prepared (substrate preparation process 50). This state is shown in FIG. 4A.

  Next, an etching process is performed on the cathode substrate 16 to form the emitter 18 at a predetermined location (emitter forming step 51), and the insulating layer 20 is formed in a predetermined region by a thin film forming process (insulating layer). Further, the gate electrode 22 is formed in a predetermined region by a thin film formation process (formation step 52) (gate electrode formation step 53). The state after the gate electrode formation step 53 is shown in FIG. 4B.

  Next, carbon ions 40 are implanted into the region including the tip of each emitter 18 (ion implantation step 54). This state is shown in FIG. 4C.

  In the above example, the carbon ions 40 are implanted into a wide region including the tip portions of the plurality of emitters 18 after the formation of the plurality of emitters 18, the insulating layers 20, and the gate electrodes 22. Also good. In short, carbon ions 40 may be implanted at least at the tip of each emitter 18 after each emitter 18 is formed. This is because it is the tip of each emitter 18 that contributes to the field emission of the electrons 12, and it is sufficient that at least the tip can be modified.

  Further, for example, carbon ions 40 may be implanted into the tip of each emitter 18 before forming the insulating layer 20 and the gate electrode 22. In that case, the carbon ions 40 may be implanted only into the tip of each emitter 18, or the carbon ions 40 may be implanted into a region including the tip of each emitter 18.

  In the ion implantation step 54 in which the carbon ions 40 are implanted, it has been confirmed by experiments and simulations that the energy and the implantation amount of the carbon ions 40 are important. This will be described in detail below.

An example of the experimental results is shown in FIG. This is because the cathode substrate 16 and the emitter 18 are mainly composed of silicon and have 1024 emitters 18 in the configuration shown in FIG. 1 and FIG. This is a measurement of a time change of an electron current (emission current) emitted from each field emission electron source 10 obtained by implanting negative carbon ions 40. Annealing is not performed after ion implantation. The emission current was measured by the current flowing through the collector electrode. The atmosphere was measured with oxygen gas introduced at 1 × 10 ⁻⁶ Pa in order to realize an oxygen-containing atmosphere. The energy of the implanted carbon ions 40 was 5 keV.

Lines A to C in FIG. 5 indicate that the implantation amount of carbon ions 40 is (A) 1 × 10 ¹⁶ ions / cm ² , (B) 3 × 10 ¹⁶ ions / cm ² , and (C) 1 × 10, respectively. ^In the case of ¹⁷ ions / cm ² . Line D is a comparative example when (D) carbon ion implantation is not performed. The initial current is about 15 μA in all cases.

  When carbon ion implantation is not performed (D), electrons are emitted, but the emission current decreases rapidly with the passage of time, indicating that the lifetime is very short. The time until the emission current is halved is about 5 hours. In contrast, with the injection amount of (A), the time until the emission current is halved is about 12 hours, the injection amount of (B) is about 20 hours, and the injection amount of (C) is 50 hours. Degree. It can be seen that the life is extended as compared with the comparative example of (D), and the life is extended as the injection amount is increased.

  Based on the above experimental results and the like, a preferable range of energy and implantation amount of the implanted carbon ions 40 was obtained by simulation.

  In order to prevent the deterioration of the electron emission characteristics by suppressing the oxidation of silicon by combining carbon atoms by ion implantation with silicon atoms constituting the emitter 18, the concentration distribution of carbon atoms in the surface layer portion of the emitter 18 is: (1) Within the depth range from the surface to a depth of about 40 nm, (2) the minimum value of the carbon atom concentration is 20%, and (3) the peak value of the carbon atom concentration is within the range of 40% to 60%. Experiments have shown that such a distribution is preferable.

An example of ion implantation conditions that satisfy this is shown in FIG. In this figure, the horizontal axis represents the carbon ion energy [keV], and the vertical axis represents the carbon ion implantation amount [× 10 ¹⁷ ions / cm ² ], and the points P _{1 to} P ₆ on this orthogonal coordinate are shown. Are expressed by (energy, injection amount), respectively (the same applies to FIGS. 7, 10, and 11).

The carbon ions 40 have points P ₁ (5,0.8), P ₂ (5,1.5), P ₃ (10,2.5), P ₄ (15,3.0), P ₅ (15 , 2.0) and P ₆ (10, 1.6) are connected under a condition within a range R ₁ (including on the straight line; the same applies hereinafter) surrounded by a straight line af. preferable. The reason is as follows. The range R ₁ is indicated by hatching in FIG. 6 (the same applies to the ranges R _{2 to} R ₄ described below).

  The reason why the lower limit value of the energy of the carbon ions 40 is set to 5 keV as shown by the line a is to secure the above-mentioned thickness (about 40 nm) of the carbon introduction layer of the surface layer portion of the emitter 18 as a minimum. A carbon-introduced layer having the above thickness cannot be formed with low energy.

  The upper limit value of the energy of the carbon ions 40 is set to 15 keV as shown by the line d. If the energy is higher than this, the carbon atoms are too deep inside the emitter 18, so that the injection amount is increased. This is because the carbon atom concentration in the above thickness range does not increase and the effect of modification by carbon ion implantation is lost.

  The upper limit of the implantation amount of the carbon ions 40 indicated by the lines b and c is to prevent the concentration on the upper limit side of carbon atoms inside the emitter 18 from exceeding 60% of the peak value. Introducing carbon at a higher concentration is not preferable because it causes expansion of the emitter 18, leading to deterioration of electron emission characteristics and destruction of the emitter 18.

  The lower limit of the implantation amount of the carbon ions 40 indicated by the lines e and f is such that the carbon atom concentration in the surface layer portion (in the range up to a depth of about 40 nm) of the emitter 18 is 20% or more of the minimum value and the peak value. It is for maintaining in the range of 40% or more. If the carbon atom concentration is lower than this range, the effect of suppressing the deterioration of the electron emission characteristics cannot be exhibited sufficiently, which is not preferable.

In the ion implantation step 54, by implanting carbon ions 40 under conditions that are within the range R _1, the carbon atom concentration distribution in the tips of the emitters 18 is bonded to the silicon atoms constituting each emitter 18 Thus, the effective distribution for suppressing the oxidation of silicon can be achieved, so that the lifetime of electron emission from each emitter 18 can be extended.

  In the manufacturing method, as described above, the annealing treatment is not performed after the ion implantation step. The annealing treatment may not be performed because the carbon atoms implanted into the surface layer portion of each emitter 18 under the above implantation conditions intervene around the silicon atoms constituting each emitter 18 so that silicon is mainly used. It is considered that the emitter 18 as a component has a state of electrical conduction rather than that of a semiconductor, and therefore, good electron emission characteristics can be expressed without annealing.

  Incidentally, in normal ion implantation for forming a semiconductor, the crystal of silicon is broken and becomes amorphous by the ion implantation, so that a recrystallization process, that is, an annealing process is required in order to obtain good characteristics as a semiconductor. Become. On the other hand, when silicon is used as the emitter in the field emission electron source, it is not always necessary to obtain good properties as a semiconductor, and it is only necessary to have the above-described metallic electrical conductivity. It is not necessary to perform processing. Of course, annealing treatment may be performed as necessary within a range where the carbon introduction layer does not change significantly.

  Therefore, according to the above manufacturing method, the field emission electron source 10 having good electron emission characteristics and a long lifetime can be obtained without performing an annealing process after the ion implantation step 54. As a result, the annealing process can be omitted, and the number of processes and the manufacturing cost can be reduced.

As in the example shown in FIG. 7, the upper limit value of the energy of the carbon ions 40 in the ion implantation step 54 may be lowered to 12 keV as indicated by the line d. In this case, preferable ranges of the implantation conditions of the carbon ions 40 are points P ₁ (5,0.8), P ₂ (5,1.5), P ₃ (10,2.5), P ₄ (12, 2.7), P ₅ (12, 1.7) and P ₆ (10, 1.6) are within a range R ₂ surrounded by connecting the straight lines a to f.

  In this way, since the upper limit value of the energy of the carbon ions 40 is reduced, carbon atoms caused by ion implantation are prevented from entering too deep into the inside of the emitter 18, and carbon within the surface layer portion of the emitter 18 is suppressed. The atomic concentration distribution can be more effectively distributed to suppress the oxidation of silicon constituting the emitter 18 more reliably.

  After the ion implantation step 54, a plasma treatment step of performing plasma treatment by irradiating at least the tip of the emitter 18 with plasma generated using a gas containing carbon may be performed.

For example, as in the example of the plasma processing step shown in FIG. 8, the plasma 42 is irradiated (incident) into a region including the tip portions of the plurality of emitters 18. This plasma treatment step can be performed using, for example, a known reactive etching apparatus. For example, the plasma 42 is obtained by converting CHF ₃ (methane trifluoride) gas into plasma. However, other than this, a gas containing carbon may be converted into plasma.

  Note that the plasma 42 may be applied only to the tip of each emitter 18 or may be applied to a wide region including the tip of each emitter 18 as in the example shown in FIG. In short, it is sufficient to irradiate at least the tip of each emitter 18. It is because the tip of each emitter 18 contributes to the field emission of the electrons 12 and it is sufficient that at least the tip can be plasma-treated.

By the plasma processing step, a carbon-based film is formed on the surface of the tip of each emitter 18, and this film functions to suppress oxidation of the surface of the tip of each emitter 18. The lifetime can be extended. The carbon-based film is a film composed of C, H, and F elements when CHF ₃ gas is used.

An example of the experimental results is shown in FIG. This is an example in which a plasma treatment with CHF ₃ plasma is further performed after carbon ion implantation under the same conditions (that is, the same energy and implantation amount) as in the case of lines A to C shown in FIG. Lines E to G correspond to lines A to C, respectively. A reactive etching apparatus was used for this plasma treatment. The plasma treatment conditions were such that the flow rate of CHF ₃ gas was 80 sccm, the gas pressure in the apparatus was 2.5 Pa, the input high frequency power was 80 W, and the plasma treatment time was 30 seconds.

  As shown by lines E to G in FIG. 9, it can be seen that, at any implantation amount, the decrease in emission current with the passage of time is much smaller than in the case of only carbon ion implantation shown in FIG. 5. . That is, it can be seen that the lifetime of the field emission electron source 10 can be extended.

FIG. 10 shows an example of a preferable range of energy and implantation amount of the carbon ions 40 in the ion implantation step 54 when a plasma treatment step is further performed after the ion implantation step 54. The carbon ions 40 have points P ₁ (5,0.8), P ₂ (5,1.5), P ₃ (10,2.5), P ₄ (15,3.0), P ₅ (15 , 1.5) and P ₆ (10, 1.0) are preferably implanted under conditions that are within a range R ₃ surrounded by connecting the straight lines a to f. The reason is as follows.

  That is, when the plasma treatment process is performed in addition to the ion implantation process 54, the carbon atom concentration near the surface of the emitter 18 (for example, up to about 10 nm) can be increased by the plasma treatment. The number of carbon atoms to be introduced into is smaller than that in the case of the ion implantation step 54 alone. For example, the carbon atom concentration on the surface of the emitter 18 by ion implantation may be 10% or more. Therefore, the lower limit of the implantation amount of the carbon ions 40 indicated by the lines e and f may be smaller than that shown in FIG. Lines a to d are the same as in FIG.

Even when the plasma treatment step is performed after the ion implantation step 54, the upper limit value of the energy of the carbon ions 40 in the ion implantation step 54 may be lowered to 12 keV as shown by the line d, as in the example shown in FIG. . In this case, preferable ranges of the implantation conditions of the carbon ions 40 are points P ₁ (5,0.8), P ₂ (5,1.5), P ₃ (10,2.5), P ₄ (12, 2.7), 6 points of P ₅ (12, 1.2) and P ₆ (10, 1.0) are within a range R ₄ surrounded by straight lines a to f. The effect by doing in this way is the same as the effect described in FIG.

  As the carbon ions 40 in the ion implantation step 54, positive carbon ions 40 or negative carbon ions 40 may be used. This is because the physical properties of carbon ion-implanted into each emitter 18 are the same.

  However, when the negative carbon ions 40 are used, referring to FIG. 4, simultaneously with the ion implantation into the emitter 18, for example, the gate electrode 22 floats electrically (that is, is electrically insulated and nowhere. Even if ion implantation is performed on an electrode that is not connected, charging of the gate electrode 22 can be suppressed to be smaller than in the case of implanting positive ions. This is simply because of the following reasons. That is, in the positive ion implantation, positive charges are accumulated more and more in the gate electrode 22 and the potential of the gate electrode 22 is increased, whereas in the negative ion implantation, the gate electrode 22 is incident as the negative carbon ions 40 are incident. Secondary electrons are emitted from the gate electrode 22 and the energy of the carbon ions 40 is in the above range, the secondary electron emission coefficient is larger than 1, so the gate electrode 22 is charged slightly positively even though negative ions are implanted. To do. However, since the kinetic energy of the secondary electrons is small, when the gate electrode 22 is positively charged, the secondary electrons are driven back to the surrounding ground potential (which is a relatively high potential for the electrons), resulting in the gate being There is no choice but to return to the electrode 22, and eventually, the charging stops at the potential of the gate electrode 22 (for example, about several volts) such that one electron is emitted with respect to one ion incidence. Therefore, since it is not necessary to suppress charging by connecting a lead wire to the gate electrode 22 in particular, the manufacturing method can be simplified.

  Further, when the carbon ions 40 are produced, negative ions can be produced more easily and in large quantities than positive ions, so that there is an advantage that it is easy to realize the implantation amount as described above. This is simply because of the following reasons. That is, when trying to make carbon ions, a typical ion source (positive ion source) typically uses the following method. (A) A carbon-based gas is flowed into the discharge chamber to generate plasma, and carbon ions are extracted. (B) Irradiate ions to a carbon target to adjust the surface state so that electrons are not released into the vacuum together with the carbon ions. The method (a) is generally used, but the hydrocarbon gas has a large adverse effect on the apparatus, such as polymerization in the discharge chamber to form a polymer compound. Although the method (b) has no such influence, it is generally difficult to produce a large amount of carbon ions by this method.

  In the case of a negative ion, a method similar to the method of positive ion (b), except that an alkali metal such as cesium is supplied to a carbon target, and electrons are released together with carbon atoms into a vacuum to generate negative carbon ions. Can be made. The negative carbon ion release efficiency is optimized, and is known to have an efficiency of, for example, about 20%. For this reason, it is easier to make carbon ions with negative ions than with positive ions.

  In addition, as a method of implanting the carbon ions 40, for example, (a) an ion implantation method in which the mass-separated carbon ions 40 are implanted, and (b) a non-mass separation type in which ions including the carbon ions 40 are implanted without mass separation. The ion implantation method (which is also referred to as an ion doping (registered trademark) method), (c) a plasma doping method in which carbon ion 40 is implanted by generating glow discharge plasma in a gas containing carbon, etc. May be adopted. In the case of the plasma doping method, the energy of the carbon ions 40 can be controlled by a negative bias voltage applied to the cathode substrate 16 (or a holder that holds the cathode substrate 16).

  The carbon ions 40 used for implantation may be atomic, diatomic, other molecular (including hydrocarbons), clusters, or the like.

  Further, in the manufacturing method according to the present invention, as shown in the example shown in FIG. 12, the second method is provided along the gate electrode 22 on the emission side of the electrons 12 with respect to the gate electrode 22 and has a large number of small holes 30. The present invention can also be applied to the manufacture of the field emission electron source 10 further including a gate electrode (also referred to as a second extraction electrode) 28. This is because the effects of carbon ion implantation and plasma treatment on each emitter 18 are the same as those of the field emission electron source 10 shown in FIG.

It is a schematic plan view which expands and shows an example of a field emission type electron source. FIG. 2 is a cross-sectional view showing an enlarged periphery of one emitter of the field emission electron source shown in FIG. 1. It is process drawing which shows an example of the manufacturing method of the field emission type electron source concerning this invention. It is sectional drawing which shows a part of manufacturing process of a field emission type electron source. It is a figure which shows an example of the result of having measured the time change of the emission current from the field emission type electron source which ion-implanted to the emitter. It is a figure which shows an example of the preferable range of the energy of ion implantation in the case of ion implantation to an emitter, and implantation amount. It is a figure which shows the other example of the preferable range of the energy of ion implantation in the case of ion-implanting into an emitter, and implantation amount. It is sectional drawing which shows an example of the plasma processing process of performing plasma processing after ion-implanting to an emitter. It is a figure which shows an example of the result of having measured the time change of the emission current from the field emission type electron source which performed ion implantation and plasma processing to the emitter. It is a figure which shows an example of the preferable range of the energy of ion implantation, and implantation amount in the case of performing ion implantation and plasma processing to an emitter. It is a figure which shows the other example of the preferable range of the energy of ion implantation, and the amount of implantation at the time of performing ion implantation and plasma processing to an emitter. It is sectional drawing which expands and shows the surroundings of the one emitter as another example of a field emission type electron source.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Field emission type electron source 16 Cathode substrate 18 Emitter 20 Insulating layer 22 Gate electrode 28 Second gate electrode 40 Carbon ion 42 Plasma

Claims (5)

In a method of manufacturing a field emission electron source having a pointed tip and an emitter mainly composed of silicon,
An ion implantation step of implanting carbon ions into at least the tip of the emitter after the formation of the emitter;
In the ion implantation step, the carbon ion energy (unit is keV) is one axis, and the carbon ion implantation amount (unit is × 10 ¹⁷ ions / cm ² ) is the other axis. When the coordinates of the points P _{1 to} P ₆ are expressed by (energy, injection amount), P ₁ (5,0.8), P ₂ (5,1.5), P ₃ (10,2.5), Carbon ions are implanted under the condition of being surrounded by a straight line connecting 6 points of P ₄ (15,3.0), P ₅ (15,2.0) and P ₆ (10,1.6). A method of manufacturing a field emission electron source. In a method of manufacturing a field emission electron source having a pointed tip and an emitter mainly composed of silicon,
An ion implantation step of implanting carbon ions into at least the tip of the emitter after the formation of the emitter;
In the ion implantation step, the carbon ion energy (unit is keV) is one axis, and the carbon ion implantation amount (unit is × 10 ¹⁷ ions / cm ² ) is the other axis. When the coordinates of the points P _{1 to} P ₆ are expressed by (energy, injection amount), P ₁ (5,0.8), P ₂ (5,1.5), P ₃ (10,2.5), Carbon ions are implanted under the condition of being surrounded by a straight line connecting 6 points of P ₄ (12, 2.7), P ₅ (12, 1.7) and P ₆ (10, 1.6). A method of manufacturing a field emission electron source. In a method of manufacturing a field emission electron source having a pointed tip and an emitter mainly composed of silicon,
An ion implantation step of implanting carbon ions at least at the tip of the emitter after the formation of the emitter;
A plasma treatment step of irradiating at least a tip of the emitter with a plasma generated using a gas containing carbon after the ion implantation step;
In the ion implantation step, the carbon ion energy (unit is keV) is one axis, and the carbon ion implantation amount (unit is × 10 ¹⁷ ions / cm ² ) is the other axis. When the coordinates of the points P _{1 to} P ₆ are expressed by (energy, injection amount), P ₁ (5,0.8), P ₂ (5,1.5), P ₃ (10,2.5), Carbon ions are implanted under the condition of being surrounded by a straight line connecting 6 points of P ₄ (15,3.0), P ₅ (15,1.5) and P ₆ (10,1.0). A method of manufacturing a field emission electron source. In a method of manufacturing a field emission electron source having a pointed tip and an emitter mainly composed of silicon,
An ion implantation step of implanting carbon ions at least at the tip of the emitter after the formation of the emitter;
A plasma treatment step of irradiating at least a tip of the emitter with a plasma generated using a gas containing carbon after the ion implantation step;
In the ion implantation step, the carbon ion energy (unit is keV) is one axis, and the carbon ion implantation amount (unit is × 10 ¹⁷ ions / cm ² ) is the other axis. When the coordinates of the points P _{1 to} P ₆ are expressed by (energy, injection amount), P ₁ (5,0.8), P ₂ (5,1.5), P ₃ (10,2.5), Carbon ions are implanted under the condition of being surrounded by a straight line connecting 6 points of P ₄ (12, 2.7), P ₅ (12, 1.2) and P ₆ (10, 1.0). A method of manufacturing a field emission electron source.   5. The method of manufacturing a field emission electron source according to claim 1, wherein the carbon ions in the ion implantation step are negative carbon ions.

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