JPS5953712B2 - semiconductor equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor device, and particularly to a metal oxide semiconductor suitable for realizing a large-scale integrated circuit.

For example, the present invention uses a semiconductor substrate such as germanium, gallium-hysterol compound, etc., and a mixture or Depositing and forming a dielectric thin film formed from a compound,
Furthermore, it is characterized in that polycrystalline silicon or the like is provided on the dielectric.

This will be explained below with reference to the drawings.

Figure 1 shows the circuit of a 1-transistor cell d-RAM (dynamic random access memory), which includes a MOS field effect transistor (T section), a capacitor (C section), a word line 11, a bit line 12 , a ground or power supply line 13, and is manufactured with the structure shown in FIG.

That is, a P-type silicon substrate 21 on which silicon dioxide 22 is formed into a desired shape with a thickness of about 1 μm is treated at a temperature of about 1000° C. to form a silicon dioxide thin film 23 with a thickness of about 700 Λ, which further functions as an electrode. A polycrystalline silicon thin film 24 is laminated to a thickness of approximately 5,000 layers by decomposing silane gas.

After forming the polycrystalline silicon thin film into the desired shapes 24 and 24', it is irradiated with arsenic ions accelerated to about 80 KV to convert the desired portions 25 and 25' of the silicon substrate 21 into n-type, and convert the desired regions 25 and 25' of the silicon substrate 21 into n-type, Form a source part. Thereafter, the substrate 21 is heat-treated at a high temperature to form a silicon dioxide thin film 26 on the substrate and polycrystalline silicon, and then the silicon dioxide thin films 23 and 26 on the drain and source parts 25 and 25' are removed into a desired shape. At this time, the silicon dioxide thin film 26 on the polycrystalline silicon thin films 24 and 24', which function as gate electrodes and drain electrodes, is also removed at the same time into a desired shape. After that, aluminum thin film 2
7, 27', etc. are formed into a desired shape to provide the circuit shown in FIG. However, the 1-transistor cell does not have an amplification function, so the capacitor shown by C in Figure 1 cannot be simply a stray capacitance, and requires a considerable area to form. . In other words, the S/N ratio is determined by the ratio C/CB between the cell capacitance C and the stray capacitance CB of the bit line, and even if the area of the C part is made to be the same as the area occupied by the transistor T, C/CB is 1/10.
At best, the S/N ratio and other factors limit the miniaturization of cells, and this has been an obstacle to further miniaturizing large-scale integrated circuits. Furthermore, in FIG. 2, the thin film 23'' is made of silicon dioxide with a dielectric constant of approximately 4, but oxides of refractory metals such as tantalum and titanium usually have a dielectric constant several times that of silicon dioxide. Therefore, if the above-mentioned hardly soluble metal oxide is used as the thin film 23'', the area of the portion C shown in FIG. 1 can be reduced to a fraction of the size.

However, the corrosive liquid used to form the poorly soluble metal oxide thin film into a desired shape usually corrodes the silicon 21 and the silicon dioxide thin film 22 that are the substrates. It is difficult to form the MOS field effect transistor into a desired shape with good reproducibility without damaging the substrate, and as a result, the yield of manufactured MOS field effect transistors is naturally low. Therefore, it is an object of the present invention to develop a dielectric film having a particularly large dielectric constant in place of the silicon dioxide thin films 23 and 23'', which is suitable for manufacturing large-scale integrated circuits and can provide a metal oxide object with good reproducibility. An object of the present invention is to provide a semiconductor device having the following features.Examples of the present invention will be described below with reference to FIG.

Figure 3 shows the negative fraction of silicon atoms of a compound or mixture formed by incorporating silicon in tantalum that can provide a tantalum pentoxide dielectric with a dielectric constant of about 24, and the negative fraction of the silicon atomic composition from the compound or mixture. The relationship between the relative permittivity ε of the formed oxide (hereinafter referred to as compound oxide) is expressed as the relative permittivity ε of tantalum pentoxide.

This is shown in relation to As is clear from the figure,
The compound oxide has an atomic composition percentage of silicon of 60%.
Even if it is formed from the above-mentioned compounds, it exhibits a value that is about twice as large as the dielectric constant of silicon dioxide, and therefore, it has a relative dielectric constant that is about twice as large as the dielectric constant of silicon dioxide.
It is suitable for miniaturizing the area of the circuit and makes it possible to realize large-scale integrated circuits. The compound becomes amorphous when the silicon atomic composition percentage is about 15% or more, and the properties of the thin film formed become similar to those of a polycrystalline silicon thin film as the silicon content increases. be. Therefore, the compound or mixture thin film can be formed into a desired shape relatively easily, and the oxide formed by anodizing the thin film can be formed into the desired shape relatively easily, as in the case of silicon dioxide. Therefore, the manufactured MOS field effect transistor is less likely to be damaged by the corrosive liquid of the compound or mixture or the corrosive liquid of the compound oxide, and can be manufactured at a high yield. It is. As a result of experiments, it has been found that preferable results can be obtained practically when the silicon atom composition percentage of the compound constituting the oxide is 10% or more. There are various methods for depositing the compound oxide on the substrate to a thickness of about 700 mm, for example, the following method.

That is, a tantalum silicon compound is sputtered,
The compound is first formed on a substrate by a vapor deposition method or the like, and then the compound is converted into an oxide by an anodization method, a thermal oxidation method, etc., or tantalum is activated sputtered in silane gas and argon gas to form the compound on the substrate. formed into
A method of converting it into an oxide, or a method of actively sputtering a tantalum-silicon compound in a mixed gas of argon and oxygen to form an oxide directly on the substrate.
Alternatively, there is a method of directly depositing the oxide onto the substrate by high frequency sputtering using a tantalum/silicon compound oxide target, but since the present invention has the above-mentioned effects, the method of depositing the compound oxide is particularly suitable. It goes without saying that the film thickness and the like are not particularly limited. In addition, since sparingly soluble metals such as tantalum, titanium, hafnium, and zirconium exhibit similar physical properties, these sparingly soluble metal atoms may be used in place of the tantalum atom in the compound oxide. Even if the present invention is carried out using a combination of multiple types of compound oxides, the effects of the present invention will not be impaired in any way, and the semiconductor component is not limited to silicon, but germanium, gallium, histo, etc. may be used. Of course it's a good thing. Furthermore, since a dielectric material formed from a poorly soluble metal containing nitrogen or carbon provides a high quality dielectric material, the above compound or mixture may be activated sputtered in a mixed gas of nitrogen or methane, etc., and argon, etc. to form nitrides or carbides,
Of course, the present invention may also be carried out by converting it into the nitride or carbide. Furthermore, although this embodiment has been described with reference to the so-called single-layer polycrystalline silicon technology shown in FIGS. 1 and 2, for example, polycrystalline silicon 24 and 24'' shown in FIG. The present invention is naturally applicable to the so-called multilayer polycrystalline silicon technology, and it goes without saying that the manufacturing method, structure, etc. thereof are not particularly limited.

Further, in the present invention, the dielectric 23'' of the C portion contributing to capacitance and the gate oxide film 23 of the MOS transistor are formed of the same material, but the oxide according to the present invention is
It is of course possible to apply this method only to the dielectric material shown in , and to form the gate oxide film with silicon dioxide.Furthermore, the oxide 23'' can be replaced with silicon nitride, alumina, etc., which has a relative dielectric constant higher than that of silicon dioxide. It is also possible to use the metal oxide semiconductor as a thin film in which an insulating film and a dielectric according to the present invention are laminated, and the structure and use of the metal oxide semiconductor are not particularly limited.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a circuit of a dynamic random access memory, FIG. 2 is a diagram showing a cross section of a metal oxide semiconductor having a capacitive component, and FIG. 3 is a diagram showing a tantalum silicon compound according to an embodiment of the present invention. This is a characteristic diagram showing the relationship between the dielectric constant ε of an oxide and the silicon atomic composition percentage of a tantalum-silicon compound. In the figure, 11... word line, 12...
... Bit line, 13 ... Ground or power supply line, 21 ... P-type silicon substrate, 23, 23'',
26...Silicon dioxide thin film, 24...
...Polycrystalline silicon thin film, 25...Drain part, 25''...Source part.

Claims (1)

[Scope of Claims] 1. In a so-called metal oxide semiconductor device formed by depositing an oxide thin film on a semiconductor substrate such as silicon, germanium, gallium/hysterol, etc., an insulating film in a portion providing a capacitor capacitance component is , tantalum, titanium, hafnium, zirconium, etc., and a dielectric material containing a semiconductor such as silicon, germanium, histho, etc. 2. In a so-called metal oxide semiconductor device formed by depositing an oxide thin film on a semiconductor substrate such as silicon, germanium, gallium/hiso, etc., the insulating film in the portion that provides the capacitor capacitance component is made of tantalum, titanium, hafnium, etc. , a dielectric material containing a hardly soluble metal such as zirconium, a semiconductor such as silicon, germanium, or histo, and an insulating film such as silicon nitride or alumina, which has a higher dielectric constant than silicon dioxide, are formed in multiple layers. A semiconductor device characterized by: