JPH0612977A - Method for manufacturing electron-emitting device - Google Patents

Abstract

(57) [Summary] [Object] To provide a method capable of accurately controlling the etching depth at the time of forming an emitter in manufacturing an electron-emitting device and thus always obtaining a uniform-shaped emitter with good reproducibility. [Structure] Before performing anisotropic etching, an etch stop layer is formed by ion-implanting a dopant into a predetermined depth position of a Si substrate. This makes it possible to accurately control the etching depth in anisotropic etching when forming the emitter, and as a result, it is possible to achieve the intended purpose.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electron-emitting device used for a flat panel display or the like which has been developed in the field of vacuum microelectronics.

[0002]

2. Description of the Related Art As display elements, various thin display elements such as a liquid crystal panel or an EL panel are being developed in addition to a cathode ray tube, and these thin display elements have a brightness, a clarity and a viewing angle. It is inferior to cathode ray tubes in such points.

Therefore, while maintaining the advantages of the cathode ray tube,
In addition, the development of ultra-thin display elements is underway in the field of vacuum microelectronics (see, for example, "J.IEE Japan, Vol.112, No.4, '92").

The flat panel display uses electron beam scanning in a conventional cathode ray tube, whereas, for example, an electron-emitting device 30 having an array of minute electron emitters as shown in FIG. By arranging each dot, the scanning of the electron beam is eliminated, thereby achieving ultra-thinning.

An electron-emitting device applied to such a flat panel display is conventionally manufactured by the procedure shown in FIG. 4, for example. That is, the SiO ₂ mask 15 is formed on the Si substrate 11 (a), and then the Si substrate 11 is anisotropically etched to form the emitter 12 having the shape shown in (b). ), The gate electrode 13 is formed. The film 14 under the gate electrode 13 is an insulating film.

[0006]

By the way, according to the above-mentioned method for manufacturing an electron-emitting device, the shape of the emitter, particularly the height, is controlled only by the anisotropic etching time control. It is difficult to control the height accurately, and it is not possible to always obtain a uniform-shaped emitter with good reproducibility. Therefore, conventionally, the positional relationship between the tip of the emitter and the gate electrode often varies,
This has been a factor in that the characteristics of each emitter cannot be made uniform.

The present invention has been made in view of the above circumstances, and in manufacturing an electron-emitting device, the etching depth at the time of forming the emitter can be accurately controlled, so that an emitter having a uniform shape can always be reproduced. The intended purpose is to provide a method that can be obtained well.

[0008]

In order to achieve the above object, the method of the present invention employs an ion implantation method as shown in FIG. After a dopant is introduced into the deep region until Si etching speed is slowed by an order of magnitude (a), on the surface of the Si substrate 1 on the ion-implanted side and at a portion corresponding to the emitter formation portion. A mask 5 is formed, and in this state, Si
The emitter 2 is formed by anisotropically etching the substrate 1 from the ion implantation surface side.

[0009]

For example, as shown in FIG. 2, when 1012 keV B (boron) ions are implanted into a single crystal Si target, the concentration of the implanted ions increases as the depth from the target surface increases, A peak is reached at a depth of about 2 μm, and the concentration sharply decreases in a region deeper than the peak depth.

When single crystal Si is etched using KOH as an etchant, the B concentration is 1 × 10.
It is known that when ²⁰ ions / cm ³ is exceeded, the etching speed becomes 1/40 slower than other parts [KE Petersen: Sias a Mechanical Material
Proc. IEEE vol.70, no.5, pp420-457 (1982)].

Therefore, when the Si substrate 1 is etched from the side of the ion implantation surface after the above-mentioned ion implantation, the etching is surely stopped at the high-concentration ion implantation layer (high dopant layer 1a). The etching depth can always be controlled to be constant. Moreover,
In the ion implantation method, the implantation depth can be accurately controlled by appropriately setting the implantation energy, so that it is possible to accurately obtain an emitter having an arbitrary height.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram for explaining the procedure of an embodiment of the method of the present invention.

First, as shown in (a), single crystal Si <1
00> Substrate 1 with B having a dose of 1 × 10 ¹⁶ ions / cm ²
Ion implantation is performed at 1012keV. By this high-energy ion implantation, the lower surface is located in the Si substrate 1 at a depth of about 1.7 μm from the wafer surface and the dopant concentration is 1 × 10 ²⁰ ions / cm ^{3 as shown in FIG.} The above high dopant 1a is formed.

Next, the upper surface of the wafer 1 (ion implantation surface)
After forming a SiO ₂ film by wet oxidation, etc.,
Patterning is performed using the photolithography technique to form a SiO ₂ mask (planar shape: square) 5 in a portion corresponding to the emitter formation portion (b).

Next, single-sided etching from the upper surface side of the wafer 1 is performed with a KOH aqueous solution. In this etching process, when the etching progresses to the high-dopant layer 1a, it becomes extremely slow and almost stopped (c).
. Therefore, the emitter 2 is obtained by ending the etching at that time.

Then, as shown in (d), the SiO ₂ mask 5 is removed and the insulating film 4 and the gate electrode (made of Al, for example) 3 on the upper surface thereof are formed. In the present invention, the dopant to be implanted into the Si substrate is not particularly limited as long as it is an ionic species capable of increasing the dopant concentration up to the condition showing the etch stop phenomenon. In addition to KOH, other solutions such as EDP (Ethylene diamine Pyrocatechol) or hydrazine (H ₂ N ₂ ) solution may be used as the Si etchant.
Furthermore, the implantation energy of the dopant is not particularly limited, but its value is appropriately selected according to the height of the emitter to be obtained.

It goes without saying that the method according to the invention can also be applied to the production of either electron emitter arrays or individual electron emitters.

[0018]

As described above, according to the present invention,
Before performing anisotropic etching, a dopant is ion-implanted into a predetermined depth position of the Si substrate to form an etch stop layer, so that the etching depth in anisotropic etching during emitter formation is accurately controlled. This makes it possible to always obtain an emitter having a uniform shape with good reproducibility. As a result, when manufacturing an electron-emitting device having an emitter array, the characteristics of each emitter in the array can be made uniform. Moreover, the reproducibility of each production can be improved.

Further, since the etch stop layer is formed by adopting an accurate ion implantation method in which the depth in the implantation direction can be easily controlled, by appropriately setting the implantation energy, an emitter having a desired height can be obtained. There is also an advantage that it can be obtained with high accuracy and reproducibility.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a procedure of an embodiment of the method of the present invention.

FIG. 2 is a graph showing an example of a dopant profile when B of 1012 keV is implanted into single crystal Si.

FIG. 3 is a diagram showing a structural example of an electron-emitting device.

FIG. 4 is a diagram showing a conventional example of a method for manufacturing an electron-emitting device.

[Explanation of symbols]

1 ... Si substrate 1a ... High dopant layer 2 ... Emitter 3 ... Gate electrode 4 ... Insulating layer 5 ... SiO ₂ mask

Claims (1)

[Claims] 1. A method of manufacturing an electron-emitting device having a minute emitter, which is used as an electron source in the field of vacuum microelectronics and the like, and which adopts an ion implantation method to obtain a predetermined depth of a Si substrate. After introducing a dopant into the deep region up to the condition that the etching speed of Si is slow by an order of magnitude, a mask is formed on the surface of the Si substrate on the ion implantation side and in a portion corresponding to the emitter formation portion, A method of manufacturing an electron-emitting device, comprising a step of anisotropically etching the Si substrate from the ion implantation surface side in this state.