JPS61239538A - Liquid metal ion source for filed emission type ion beam generator - Google Patents

Abstract

PURPOSE:To obtain a liquid metal ion source enable of selective generation of impurity ions for forming P-type and N-type electrodes from single ion generating section without replacing the ion source by specifying the composition of atomic % in four element alloy of Au-Si-Be-Ge. CONSTITUTION:It is four element alloy of Au-Si-Be-Ge having atomic % composition of (71+ or -8):(10+ or -1.5):(10+ or -3):(9+ or -3). Said alloy has low melting point and optimal as a liquid metal ion source for field emission type ion beam generator. Since typical N-type impurities or Si, Ge and typical P-type impurities or Be are contained in said alloy, various semiconductor device can be produced without replacing the ion source in the way of process.

Description

Detailed Description of the Invention (Field of Industrial Application) This invention relates to a liquid metal ion source for a field emission type ion beam generator used in ion processing equipment, ion implantation equipment, etc. It is suitable for forming electrodes of semiconductor devices.

(Conventional technology) When forming electronic devices such as lasers, light emitting diodes, photodetectors, and other optical devices, bipolar transistors, field effect transistors, etc. on semiconductor substrate crystals such as gallium arsenide, conventional j-mask alignment is used. 1°, which used to be complicated work, but recently it has been reduced to submicron order [,,,,.

Maskless ionization using a focused ion beam [
.

According to this, a tumor injection method has been proposed.
J. 6 Ka1, □. . Tso. . f/(42 and □) It is thought that it is possible to control the process entirely by software without making any changes to Niredware.

In this case, impurity ions are implanted into the semiconductor, and maskless process is impossible at this stage.
' - electrode type electrode is formed after the roll, but in the past,
In reality, a metal electrode film is formed using a mask.

For example, in the case of a ■-v group compound such as GeAs, impurity ions such as 8i are implanted into the semiconductor to form an outer mold implantation layer, and a mass 1' is used on the n-type implantation layer. Then, a metal electrode film such as a 9-0 film is formed, or a p-type implantation layer is formed by implanting impurity ions such as Be. -Zn
A metal electrode film such as a film is formed.

In other words, with the conventional method! ! The electrode film is formed using a mask, and therefore all processes for forming various devices can be performed without a mask, and the merits of the maskless process are not fully utilized.

In view of the above-mentioned circumstances, the inventors of the present application filed a separate application and proposed that a b evaporate a metal film such as
#84 on the h film on the ion, mu ion or S4 implanted region.
Ions are implanted to cause modification in this B membrane, and then the entire surface of the B membrane is etched, one gland in the area where no modification occurs is removed, and the membrane in the area where modification is made is etched. We proposed a method for manufacturing semiconductor devices that uses films as electrodes.

According to this method, electrodes can be formed without using a mask, so the entire process of semiconductor device manufacturing can be performed without a mask.

It is known that in this case, if G- ions are used instead of st ions, an n-type electrode layer with better electrical characteristics can be obtained.

- (Problem to be solved by the invention) By the way, when using the above method, it is necessary to replace various ion sources in the middle of the process. It is necessary to perform axis alignment with strict precision between the ion deflection electrode systems.Furthermore, when performing a second ion implantation on top of an already implanted pattern with submicron precision or higher, it is necessary to replace the ion source. If the position of the ion generating section shifts even slightly, it will take a lot of effort to adjust the position, and the advantages of the above-mentioned method are not fully utilized.

On the other hand, if impurity ions for forming p-type, n-type, and electrode types could be selectively generated from one ion generating section without replacing the ion source, it would be possible to generate ions during most integrated circuit device fabrication processes.・−Change of software,
Highly integrated on the same board with only software control without any adjustments.High reliability. The advantages of the above-mentioned method, which has been filed separately, are also fully utilized.

The purpose of this study is to propose a body metal ion source.

(Means for Solving the Problems) In order to solve the above problems, in this invention) ag −
A quaternary alloy of Si-Be-Gs, m: 8
The ratio of i:Be:G- is (71±a):(to±
1.5): (10±5): (9±6) We propose a liquid metal ion source for an electron-emitting ion beam generator having a composition of (9±6) atoms.

That is, Ash-Si, Ash-Bg, and Ash-Si shown in FIG.
ML-GeJ - As is clear from the respective alloy phase diagrams, Beni-8 (approximately 70:50 atomic ratio) exhibits a melting point of 400°C or less, and Ike-B# has a B# ratio of 20 to 40 atomic ratios. at 600℃
Gs is an alloy with a ratio of approximately 73:27 atoms and a melting point of 400°C or less.

Therefore, the quaternary alloy of the present invention, which is a mixture of the above binary alloys, has a melting point of at least 600°C or lower.

In addition, if the composition deviates from the above, the melting point of the alloy will increase,
It is no longer suitable as a liquid metal ion source for field emission type ion beam generators.

(Effects of the Invention) The quaternary alloy according to the present invention has a low melting point and is optimal as a liquid metal ion source for a field emission type ion beam generator.

In addition, the quaternary alloy according to the present invention contains Si and G-, which are typical external impurities, and B#, which is a typical p-type impurity.
, it is possible to manufacture various semiconductor devices without replacing the ion source during the process.

Furthermore, the quaternary alloy according to the present invention contains 8 (, Ge).

-7 The advantage of being able to perform one step without using a mask can be fully utilized.

(Example) The present invention will be explained below based on illustrated embodiments.

FIG. 2 shows an example of implanting ions into a substrate crystal using the quaternary alloy of the present invention as a liquid metal ion source.
is a field emission type ion generator, and a quaternary alloy 3 is loaded as a liquid metal ion source into a reservoir near the tip of an emitter electrode. When the emitter electrode is heated to a predetermined temperature and the alloy 3 is melted, a voltage of several KV is applied to the emitter polarizer and the ion extraction electrode located in front of it. When a pressure is applied, an ion beam j containing a mixture of four elements is emitted from the ion generating section by field evaporation, field ionization, etc., and is guided to the mass separator 9 through the pre-calibration focusing system 61. The light is focused by the crystal 10, and a predetermined pattern is drawn 1 on the substrate crystal 15 by the deflection electrode 1 in the same manner as described above.

In addition, after evaporating hxPA% on the surface of the substrate crystal/coat in which the p-type impurity implantation region and the outer mold impurity implantation region were formed by ion implantation as described above, the Au film on the p-type impurity implantation region and the conductive substrate were deposited. An 8g ion beam is implanted from the ion generating part l near the boundary with the ion beam to cause ion beam mixing. Next, Au ion beam Y is implanted into the Au film to modify the Au film, and Ge ion beam is implanted into the Au film on the outer mold impurity implanted region, and then A
Inject u ions l and ffAt! film! Modify Casey Wake up Ron.

Furthermore, the entire surface of the film described above is etched to remove the part of the film that does not cause modification, and then etched at 400~
An ohmic electrode was formed on the part of the B film that had been modified by a4I conversion at 500°C.

According to such a method, the entire process of semiconductor device manufacturing can be performed maskless and without replacing the ion source.

Moreover, according to such a method, an ohmic electrode can be formed.

As mentioned above, by using the quaternary alloy according to the present invention as a liquid metal ion source in a field emission type ion beam generator, it is possible to generate ion-type, p-type, and impurity ions for electrode formation with one ion source. Therefore, arbitrary impurity ions can be continuously implanted onto the same substrate crystal without replacing the ion source during the ion implantation process, and ohmic electrodes of the formed devices can also be formed.
Utilizing the recently proposed maskless ion implantation using a focused ion beam on the order of submicrons, highly integrated electronic devices and original devices can be easily formed.

[Brief explanation of drawings]

Figure 1 shows the phase diagrams of AM-84, Am-B#, and AM-Ge alloys, Figure 1 (α) is the phase diagram of h-84, and Figure 1 (b) is the phase diagram of Mu-chest. , FIG. 1 (61 is a state diagram of MuG#, and FIG. 2 is a liquid metal engine according to the present invention.
:15. 1 is a diagram schematically showing a method for implanting ions into a substrate crystal using an on-source.

Claims (1)

[Claims] Au-Si-Be-Ge quaternary alloy, Au:S
The ratio of i:Be:Ge is (71±8):(10±1.5
):(10±3):(9±3) atomic % of a liquid metal ion source for a field emission type ion beam generator.