JPS625635A - Forming method for electrode of electronic device - Google Patents

Abstract

PURPOSE:To obtain an ohmic electrode having heat resistance of 550 deg.C or higher for a sinter by accumulating a high melting point metal on the surface of a silicon, ion implanting, then annealing to selectively form a silicide layer, heat treating in nonreduced atmosphere, and then forming aluminum electrode wirings which contain Si. CONSTITUTION:A field oxide film 12 is formed on a P-type single crystal Si substrate 11. After the surface of a silicon is then cleaned, an Mo film 13 is formed by sputtering. Then, Si ions are implanted through the film 13 to mix the boundary of the substrate 11 and the film 13. Subsequently, after As ions of dopant ions are implanted, it is annealed at 550 deg.C in H2 gas, an unreacted Mo film on the film 12 is then etched to selectively form an MoSi2 film 14, and an As doping layer 15 is formed in a self-aligned manner on the film 14. Thereafter, after an interlayer SiO2 film 16 is accumulated, a heat treatment of 900 deg.C is performed, a contacting hole is then formed, an Al-Si film is then formed, and A-Si electrode wirings 17 are formed by photoetching.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing heat-resistant ohmic electrodes and Schottky electrodes for silicon semiconductor devices using aluminum metal for electrode wiring.

(Prior Art) Conventional manufacturing methods for ohmic electrodes and scimitar key electrodes that use aluminum-based metal as electrode wiring have improved heat resistance against sintering performed after aluminum-based electrode wiring is formed, for example.
Journal of Applied Physics (Jou)
rnal of Applied phy81e3)
Magazine Vol. 50 No. 11 No. 6915-6926 (1979
After depositing Mo, a high melting point metal, on the silicon surface where electrodes are to be formed, as described in
A method is known in which aluminum electrode wiring is formed after annealing is performed to form MoSi2 of ~2500A. This method is intended to use Mo511g formed by thermal reaction as a barrier layer to prevent interdiffusion between aluminum and silicon.

(Problems to be Solved by the Invention) However, when the ohmic electrode formed by the conventional method is sintered at 534°C for 30 minutes, MoSi formed by the thermal reaction and pinholes in the film are removed. Te Mo Si! It is shown that the underlying silicon is transferred into the aluminum electrode wiring and lacks the barrier properties of the Mo Si 2 film. A major reason why high melting point metal silicide exhibits insufficient heat resistance against sintering is the non-uniformity of the film quality of the high melting point metal silicide film formed by thermal reaction.

An object of the present invention is to provide a method for manufacturing an ohmic electrode and a Schottky electrode that have a heat resistance of at least 550° C. against sintering.

(Means for Solving the Problems) According to the present invention, there are a step of depositing a high melting point metal on a surface of single crystal silicon or a surface of polycrystalline silicon on which an electrode is to be formed, and a step of depositing a high melting point metal on the surface of single crystal silicon or polycrystalline silicon on which an electrode is to be formed, and performing ion implantation to deposit the high melting point metal. The interface with the silicon surface is mixed, annealing is performed at 400 to 600'C, and then the high melting point metal remaining without any reaction is etched away, and the silicide layer of the high melting point metal is formed into the electrode. A process of selectively forming on a single crystal silicon surface or a polycrystalline silicon surface, a process of heat treatment in a non-reducing atmosphere at a temperature of 800°C or more, and an AA'it electrode wiring containing Si on the surface of the silicide layer. A method for forming a pole of an electronic device is obtained, the method comprising the step of contacting the electrode.

(Function) In the present invention, the high melting point metal silicide interposed as a barrier metal between the aluminum-based electrode wiring and the silicon surface is formed by ion implantation through the high contact point metal film formed on the silicon surface. 1iA
Because it is formed by a method of mixing the interface with Il and then annealing at 400 to 600°C to form silicide, it has a smooth and uniform film quality.
Aluminum system of silicon via pinhole etc. = a
Transfer of wiring is suppressed, making it effective as a barrier metal. The reason why the temperature is limited to 400 to 600 DEG C. is that if high-temperature annealing is suddenly performed after ion implantation, silicide will be formed protruding and self-alignment will be lost.

The reason why the second annealing is performed in a non-reducing atmosphere at 800° C. or higher is to simultaneously lower the resistance of the silicide and recover damage caused by ion implantation while maintaining smooth and uniform film quality.

Furthermore, if the Si content in the AJ electrode wire is too high, Si precipitates may be formed during sintering, resulting in high resistance, so it is preferably 3% by weight or less.

(Example) Hereinafter, the soil spreading method of the present invention will be explained with reference to the illustrated examples. FIGS. 1(a) to 1(d) are schematic cross-sectional views showing an example of the manufacturing process of the present invention.

First, acceptor density W 6.5 x 10” Cnt=
A P-type single crystal Si substrate 11 is dosed with 1 ordinary LOCO8.
A field oxide film 12 of 500A was formed by the method (FIG. 1(a)). Next, after cleaning the silicon surface on which a silicide layer is to be formed with a dilute HF solution, a Mo film 13 of +Q4ooA is formed by magnetron sputtering.
was formed to have the structure shown in FIG. 1(b). Next, a Mo film 13 was formed.
Si ion implantation through ion energy 80 ke
5×101scIrL-2 rows at V, silicon substrate 11
After mixing the interface between the MO film 13 and the MO film 13, A8 ions, which are dopant ions, are irradiated with I at an ion energy of 140 keV.
After injecting X I Q"cm-", 5
Annealing was carried out at 50°C for 20 minutes, and then the temperature was 0.5°C. Unreacted Mo on the field oxide film 12 is removed using an etching solution.
By etching the film, a Mo Si@ film 14 is selectively formed as shown in FIG. 1I(e), and M
An As doped layer 15 was formed on the Si film 14 with a self-aligning force. Next, a 5-inch interlayer film 16 with a thickness of 6,500 layers was deposited by the CVD method, and then Si was deposited at 900°C to make the film denser
, heat treatment was performed for 20 minutes, and then, after opening a contact hole, 1.2 μm of Al-2% Si was formed by sputtering, and A
A 1-2% Si electrode wiring i7 was formed to obtain the structure shown in FIG. 1(d). kl- formed according to the above procedure of the present invention
2%Si/Mog 1t/n-p (junction depth 0
．． 16μm) electrode (joint surface at; 300/jmX3
00μm.

Figure 2 shows the reverse voltage dependence of reverse current after sintering Al-2 (iS f/MoS t, contact area: 250 Arn x 40 μm) at 550°C for 30 minutes (measurement sample Number 5). In the region of reverse voltage below 10V, which is the normal operating voltage, the leakage current is small on the order of 10-''A.Leakage current at this level can only be created by As ion implantation, which is currently used as electrodes in silicon devices. n-p junction (junction depth 0.
The leakage level is almost the same as that after sintering at 450° C. (25 μm). An evaluation index of the barrier properties of a barrier metal formed on a pn junction is the relationship between leakage current and junction depth, and this is true when formed by the manufacturing method of the present invention.

Even when the junction depth is as shallow as 0.13 μm, the junction depth is 0.
．． A similar leakage level was observed for a depth as deep as 26 μm. FIG. 3 shows the values of reverse leakage current at a reverse voltage of 5 .ANG. when sintering was performed for 30 minutes at 450.degree. C., 500.degree. C., and 550.degree. C. for the sample formed according to the embodiment shown in FIG. The difference in reverse leakage current due to the difference in sinter degree is about 1 pA.

(Effects of the Invention) As described above, it can be seen that the ohmic electrode formed by the manufacturing method of the present invention has heat resistance against sintering up to 550°C. Furthermore, although the junction depth of the Koyoro ohmic electrode manufactured by the manufacturing method of the present invention is very shallow at 0.15 μm and 8 degrees, including the 0.1 μm thickness of the MoSiZ film, it has a sinter heat resistance of 550 degrees Celsius. ' in micro semiconductor devices represented by submicron MO8FETs
Useful for rt poles. In particular, the manufacturing method of the present invention can produce high-temperature sintering at 550°C, which can sufficiently recover damage introduced to the MO8 interface when a beam beam or X-ray exposure is used to process aluminum-based metal wiring to submicron dimensions. The electrode I can be implemented. In the above embodiment, AI! Although the case of an n-p junction formed by implantation is shown, the case of a p-n junction formed by B injection is equally effective. Furthermore, sinter heat resistance of 550° C. was ensured even when the Schottky electrode was formed only by Si pouring without dopant ion implantation. He's talented.
In the example? vIc) Although the case where a Si film was used as the barrier metal was shown, the cases of WSi2 and Ta5il were equally effective. Further, in the above embodiment, the case of single crystal silicon was described, but the same applies to the case of polycrystal silicon. For example, when used for the gate electrode contact of the Mos transistor resistor 24, good, ie, low contact resistance could be maintained.

[Brief explanation of drawings]

FIGS. 1(a) to 1(d) show an embodiment of the present invention. In the figure, 11 is a P-type Si substrate, 12 is a field oxidation sample, 1
3 is a Mo film, 14 is a Mo S t t film, 15 is a doping layer, 16 is an interlayer SiO film, 17 is an Al-2φ
The Si'α pole wiring is shown. Figure 2 shows the Al-2%S, MoSi,/n-P junction formed by this method at 550°C.
, Reverse characteristic diagram after 30 minutes of sintering. FIG. 3 is a diagram showing the dependence of leakage on the sinter temperature If in the opposite room EE5V at 450° C., 500° C., and 550° C. as above. 1st (2) Figure 2 AL-2'105J105J? /n”-F# 550
'C 230 minutes of Shishita vagina's existence, poetry, and Gyakurikima V,
Ten thousand (V゛)

Claims (1)

[Claims] A step of depositing a high melting point metal on the single crystal silicon surface or polycrystalline silicon surface on which an electrode is to be formed, ion implantation to mix the high melting point metal and the silicon surface, and heat treatment at 400 to 600°C. Thereafter, the high melting point metal remaining without reaction is removed by etching, and a silicide layer of the high melting point metal is selectively formed on the silicon surface where the electrode is to be formed. A method for forming an electrode for an electronic device, comprising the steps of performing heat treatment in a non-reducing atmosphere and forming an Al electrode wiring containing Si in contact with the surface of the silicide layer.