KR101892632B1 - Semicontuctor memory device having platinum group oxide-tin oxide compound and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a semiconductor memory element having a compound of a platinum group oxide and a tin oxide, and a manufacturing method thereof. The semiconductor memory element according to embodiments of the present invention comprises: a lower electrode; a dielectric layer formed on the lower electrode; and an upper electrode formed on the dielectric layer, wherein the lower electrode or the upper electrode includes a compound of a platinum group oxide and a tin oxide.

Description

TECHNICAL FIELD [0001] The present invention relates to a semiconductor memory device having a compound of a platinum group oxide and a tin oxide, and a method of manufacturing the same. [0002]

The present invention relates to a semiconductor memory device and a method of manufacturing the same, and more particularly, to a semiconductor memory device including an electrode including a compound of a platinum group oxide and a tin oxide, and a method of manufacturing the same.

Through the breakthrough of the semiconductor device process, the degree of integration of semiconductor devices is rapidly developing. In particular, memory semiconductor devices such as DRAM are required to develop ultrafine integrated devices such as a process using a design rule of 20 nm or less. The biggest obstacle to the miniaturization of DRAM devices is the capacitor technology, which is the core technology of DRAM element technology. A capacitor for storing charges for recording "1" and "0" information is required to maintain a low leakage current under an operating voltage and at the same time to secure a large capacitance. In order to satisfy such a condition, It is necessary to develop an electrode material capable of securing a low leakage current.

Conventionally, TiN is used as an electrode material, and silicon oxide (SiO ₂ ) and aluminum oxide (Al ₂ O ₃ ) are mainly used as a dielectric material. However, the development of next generation 10nm DRAM devices is difficult to apply the existing materials, so it is essential to develop new dielectrics and electrodes.

Of the dielectric candidates to be used in next-generation DRAM devices, titanium oxide (TiO ₂ ) of rutile structure, which can have a dielectric constant of 80 or more, has attracted considerable attention. However, since titanium oxide having a rutile structure, which is a high temperature stable phase, requires a high temperature of 700 DEG C or higher, it is difficult to form the titanium oxide in a general semiconductor process. To solve this problem, it is possible to form a rutile-structured titanium oxide even at a low temperature of 300 degrees or less by using an electrode material having a rutile structure such as RuO ₂ or IrO ₂ .

 However, the platinum group oxide electrode having a rutile structure has a weak point that it is reduced by the reduction heat treatment process that is essential for the DRAM manufacturing process and deteriorates the device. In the case of a conventional TiN electrode having a high reduction resistance, it is difficult to form a rutile phase of titanium oxide, which is difficult to apply.

Therefore, it is required to develop a new electrode material having a structure capable of forming a rutile-type titanium oxide and having a high reduction resistance.

US registered patent US 8765569 B2

The present invention provides an electrode that can withstand a heat treatment process in a reducing atmosphere and has a high reduction resistance and a method of manufacturing the same.

A semiconductor memory device having a compound of a platinum group oxide and a tin oxide according to an embodiment of the present invention includes a lower electrode, a dielectric layer formed on the lower electrode, and an upper electrode formed on the dielectric layer, The upper electrode includes a compound of platinum group oxide and tin oxide.

In one embodiment, the platinum group oxide includes at least one of ruthenium oxide (RuO ₂ ), iridium oxide (IrO ₂ ), osmium oxide (OsO ₂ ) and rhodium oxide (RhO ₂ ) tin oxide may include tin dioxide (SnO _2).

In one embodiment, the upper electrode or the lower electrode may be doped with at least one of fluorine (F), tantalum (Ta), antimony (Sb), and niobium (Nb).

In one embodiment, the semiconductor memory device may be a DRAM capacitor.

In one embodiment, a semiconductor memory device having a compound of a platinum group oxide and a tin oxide, wherein the dielectric layer comprises titanium oxide of a rutile structure.

A method of fabricating a semiconductor memory device having a compound of a platinum group oxide and a tin oxide according to an embodiment of the present invention includes the steps of forming a lower electrode on a substrate, forming a dielectric layer on the lower electrode, Wherein the lower electrode or the upper electrode comprises a compound of platinum group oxide and tin oxide.

In one embodiment, the step of forming the lower electrode or the step of forming the upper electrode may be performed by sputtering, atomic layer deposition (ALD), electron beam evaporation (E-beam evaporation), thermal evaporation, A compound layer of a platinum group oxide and a tin oxide can be formed using at least one of molecular beam epitaxy (Molecular Beam Epitaxy), pulsed laser deposition (PLD), and chemical vapor deposition (CVD).

In one embodiment, the step of forming the lower electrode or the step of forming the upper electrode may include a step of forming a tungsten oxide layer on the tungsten oxide layer by depositing fluorine (F), tantalum (Ta), antimony (Sb), or niobium The method may further include doping at least one.

In one embodiment, the platinum group oxide includes at least one of ruthenium oxide (RuO ₂ ), iridium oxide (IrO ₂ ), osmium oxide (OsO ₂ ), and rhodium oxide (RhO ₂ ) the tin oxide may include tin dioxide (SnO _2).

According to one embodiment of the present invention, a mixed electrode film having a rutile structure, which is not limited to a heat treatment process, can be used for a semiconductor memory device. In particular, a DRAM device having a design rule of 10 nm can be manufactured by applying a titanium oxide film having a high dielectric constant as a dielectric of a DRAM capacitor.

1 is a cross-sectional view of a semiconductor memory device having a compound of a platinum group oxide and a tin oxide according to an embodiment of the present invention.
FIG. 2 is an X-ray diffraction pattern according to one embodiment of Sn in composition of RuO ₂ and tin dioxide. FIG.
FIG. 3 shows an X-ray diffraction pattern before and after the reduction heat treatment, in which a RuO ₂ -SnO ₂ compound is used as a lower electrode and TiO ₂ is formed thereon as a dielectric layer and the composition ratio of Sn is varied according to an embodiment of the present invention .
FIG. 4 is a graph showing the results of the comparison between FIG. 4 and FIG. 3, in which TiO ₂ is formed on the lower electrode made of only SnO ₂ (FIG. 4A) and the lower electrode made of RuO ₂ (FIG. X-ray diffraction pattern.
FIGS. 5 and 6 show the results of different ratios of RuO ₂ and SnO ₂ in the RuO ₂ -SnO ₂ compound applied to electrodes in one embodiment of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises ", or" having ", or the like, specify that there is a stated feature, number, step, operation, , Steps, operations, components, parts, or combinations thereof, as a matter of principle.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be construed as meaning consistent with meaning in the context of the relevant art and are not to be construed as ideal or overly formal in meaning unless expressly defined herein . Like reference numerals in the drawings denote like elements. In the following description, well-known functions or constructions are not described in detail to avoid unnecessarily obscuring the subject matter of the present invention. In addition, the size of each component in the drawings may be exaggerated for the sake of explanation and does not mean a size actually applied.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

A semiconductor memory device having a compound of a platinum group oxide and a tin oxide according to an embodiment of the present invention uses a compound of a platinum group oxide and a tin oxide as an electrode material.

1 is a cross-sectional view of a semiconductor memory device having a compound of a platinum group oxide and a tin oxide according to an embodiment of the present invention. 1, a semiconductor memory device 100 having a compound of a platinum group oxide and a tin oxide includes a substrate 110, a contact plug 120, a lower electrode 130, a dielectric layer 140, and an upper electrode 150 can do. In one example, it may be a semiconductor memory device 100 DRAM capacitor having a compound of platinum group oxide and tin oxide. Also, the contact plug 120 may be made of tungsten.

Referring to FIG. 1, a semiconductor memory device 100 having a compound of a platinum group oxide and a tin oxide includes a lower electrode 130 on a contact plug 120, a dielectric layer 140 on a lower electrode 130, . The upper electrode 150 may be formed on the dielectric layer 140.

Each of the components 120-150 may be patterned to suit the application and have a concave-convex structure as shown in FIG.

The contact plug 120 may be constructed of any conductive material.

The dielectric layer 140 may include titanium oxide of a rutile structure. When the dielectric layer 140 is used as the rutile titanium oxide, the lower electrode also needs to be a rutile structure. Therefore, it is very important to maintain the rutile structure as well as the reduction resistance of the lower electrode.

In one embodiment of the present invention, the lower electrode 130 or the upper electrode 150 may include a compound of a platinum group oxide and a tin oxide.

Tin oxide in one embodiment may comprise a tin dioxide (SnO _2).

The platinum group oxide may be at least one of ruthenium oxide (RuO ₂ ), iridium oxide (IrO ₂ ), osmium oxide (OsO ₂ ), and rhodium oxide (RhO ₂ ). The rutile structure electrode material has an advantage that it can induce low-temperature rutile growth of TiO ₂ used as a capacitor dielectric material of a DRAM device and at the same time has a high work function and can suppress a leakage current.

On the other hand, when the electrode material is composed only of a platinum group oxide, the platinum group oxide has a characteristic that the bonding force with oxygen is not so small and is easily reduced. In particular, in the fabrication process of a DRAM device, heat treatment in a hydrogen atmosphere is inevitably accompanied by improvement of the transistor performance. In the heat treatment process, the platinum group oxide electrode is easily reduced, and dissociated oxygen oxidizes the contact plug (tungsten material) .

Therefore, although the electrode composed of the platinum group oxide is more excellent in terms of leakage current than the metal electrode, it is difficult to use the electrode compared to the metal electrode.

In one embodiment of the present invention, the electrodes 130 and 150 can solve the above problems by using a compound of platinum group oxide and tin oxide. Specifically, tin dioxide has a rutile structure and is excellent in reduction resistance and can not easily be reduced even in the heat treatment of hydrogen. Therefore, the above problems can be solved by producing and using a compound together with the platinum group oxide.

That is, in the present invention, it is possible to use both a platinum group oxide and a tin oxide compound as an electrode material to have both rutile-type platinum group oxides exhibiting excellent electrical properties and tin dioxide characteristics having excellent reduction resistance.

In one embodiment, the upper electrode 150 or the lower electrode 130 may be doped with at least one of fluorine (F), tantalum (Ta), antimony (Sb), and niobium (Nb).

A method of fabricating a semiconductor memory device having a compound of a platinum group oxide and a tin oxide according to an embodiment of the present invention can manufacture a semiconductor memory device having the compound of the platinum group oxide and the tin oxide.

In one embodiment, a method of fabricating a semiconductor memory device having a compound of a platinum group oxide and a tin oxide includes the steps of forming a lower electrode on a substrate, forming a dielectric layer on the lower electrode, and forming an upper electrode on the dielectric layer . At this time, the lower electrode or the upper electrode may contain a compound of platinum group oxide and tin oxide.

In one embodiment, the platinum group oxide includes at least one of ruthenium oxide (RuO ₂ ), iridium oxide (IrO ₂ ), osmium oxide (OsO ₂ ), and rhodium oxide (RhO ₂ ) having a rutile structure, May comprise tin dioxide (SnO ₂ ).

The step of forming the lower electrode or the step of forming the upper electrode may be performed by a sputtering method, an atomic layer deposition (ALD) method, an E-beam evaporation method, a thermal evaporation method, A compound layer of a platinum group oxide and a tin oxide may be formed by using at least one of a molecular beam epitaxy (Molecular Beam Epitaxy), a pulse laser deposition (PLD) method, and a chemical vapor deposition (CVD) method.

For example RuO ₂ -SnO case of forming the _second compound by the atomic layer deposition method, to form RuO ₂ Cycle repetition can be performed by performing one cycle of the four steps of the Ru raw material injection and purging, the oxygen raw material injection and the purge step.

The precursor of Ru may be Ru (Cp) ₂ , Ru (MeCp) ₂ , Ru (EtCp) ₂ , Ru (tmhd) ₃ , Ru (mhd) ₃ , RuO ₄ , RuCl, RuCl ₃ , (ethylcyclopentadienyl) Ru, Ethylbenzene (1-ethyl-1,4 cyclohexadiene) Ruthenium, bis (methylallyl) (1,5-cyclooctadiene) Ru and the like.

The oxygen source may be at least one of oxygen, oxygen plasma, ozone, and the like, but is not limited thereto.

Although Ru has been described above as a platinum group material, the same approach can be used for other platinum group metals.

The atomic layer deposition of SnO ₂ in the compound of the platinum group oxide-tin oxide can be carried out by constituting the four steps of the injection of the Sn raw material and the purge, the injection of the oxygen raw material and the purging in one cycle similarly to the atomic layer deposition of RuO ₂ .

The raw material for Sn is _{[[(CH 3) 3 Si} ] 2 N] 2 Sn, [(C 6 H 5) 3 Sn] 2, (H 2 C = CHCH 2) 4 Sn, [(C 2 H 5) _{2 N] 4 Sn, [(} CH 3) 2 N] 4 Sn, Sn (CH 3) 4, Sn (CH = CH 2) 4, C 1 0H 14 O 4 Sn, (C 6 H 11) 3 SnH, C ₆ H ₅ C = CSn (CH ₃ ) ₃ , C ₆ H ₅ Sn (CH ₃ ) ₃ , and SnCl ₄ . The oxygen source may be, but is not limited to, H ₂ O, oxygen plasma, ozone, and the like.

In the various embodiments of the present invention, the compositional change in the platinum group oxide (RuO ₂ ) -SnO ₂ compound can be controlled by changing the ratio of the number of cycles of atomic layer deposition of the platinum group oxide (RuO ₂ ) and SnO ₂ .

In one embodiment, the step of forming the lower electrode or the step of forming the upper electrode may include at least one of fluorine (F), tantalum (Ta), antimony (Sb), and niobium (Nb) The method may further include a step of doping.

The step of forming the dielectric layer may be performed in at least one of the above-described methods of forming the electrodes (ALD, CVD, etc.). Further, the step of forming the dielectric layer may be performed in the same or different manner as the step of forming the electrode.

Hereinafter, experimental results according to an embodiment of the present invention will be described. In the following experiment, a case where a lower or upper electrode is formed using RuO ₂ and a compound of tin dioxide and a dielectric layer is formed using TiO ₂ has been described. However, in the following description, when the platinum group oxide is a platinum group oxide other than RuO ₂ As shown in FIG.

FIG. 2 is an X-ray diffraction pattern according to one embodiment of Sn in composition of RuO ₂ and tin dioxide. FIG. Specifically, FIG. 2 shows an X-ray diffraction pattern when the Sn / (Sn + Ru) composition is 8.21 to 98.8 at%. Referring to FIG. 2, it was confirmed that the compound thin film was formed in a rutile structure in the total composition region where the Sn / (Sn + Ru) composition reached about 8 to 99 at%, and the lattice constant was increased as the SnO ₂ composition was increased . This increase in lattice constant is due to the different lattice constants of RuO ₂ and SnO ₂ .

FIG. 3 shows an X-ray diffraction pattern before and after the reduction heat treatment, in which a RuO ₂ -SnO ₂ compound is used as a lower electrode and TiO ₂ is formed thereon as a dielectric layer and the composition ratio of Sn is varied according to an embodiment of the present invention . 4 is a graph showing the relationship between the thickness of TiO ₂ formed on the lower electrode made of only SnO ₂ (FIG. 4A) and the surface of RuO ₂ alone (FIG. 4B) Front and back X-ray diffraction patterns. 3 and 4, the reduction heat treatment was conducted in a reducing atmosphere of H ₂ (4%) / N ₂ (96%) at 400 ° C. for 30 minutes.

3 and 4, peak peaks indicating rutile phase were observed in all the experimental examples before the reduction heat treatment. For reference, in FIG. 3, when SnO ₂ is 8.21 at%, the marked portions indicate peaks. That is, referring to FIG. 3, it means that TiO ₂ on rutile can be formed on the compound electrode of SnO ₂ and RuO ₂ .

Particularly, after the reduction annealing, it can be seen that the rutile peak disappeared in the structure of RuO ₂ alone (FIG. 4 (b)). This rutile peak disappeared because RuO ₂ was reduced to Ru.

However, it is noteworthy that RuO2-SnO2 compounds have a rutile peak even after the reduction heat treatment even when Sn content is as low as 8 at%. These results indicate that RuO ₂ -SnO ₂ compound can be used as an electrode to form rutile TiO ₂ with high dielectric constant on it, as well as reduction resistance.

Therefore, the use of platinum group oxide-tin oxide compounds as electrodes for DRAM capacitors using rutile TiO ₂ as a dielectric material will be greatly enhanced.

FIGS. 5 and 6 show the results of different ratios of RuO ₂ and SnO ₂ in the RuO ₂ -SnO ₂ compound applied to electrodes in one embodiment of the present invention. Referring to FIG. 5, it can be seen that the ratio of Sn increases linearly as the ratio of the number of cycles forming SnO ₂ increases in forming the RuO ₂ -SnO ₂ compound. Referring to FIG. 6, the resistance of the sheet (electrode) is shown to be small in the composition of SnO ₂ of less than 20% in the RuO ₂ -SnO ₂ compound. In view of the above, the RuO ₂ -SnO ₂ compound according to an embodiment of the present invention preferably has a ratio of RuO ₂ to SnO ₂ of 5: 1 to 6: 1 in consideration of resistance, But is not limited to.

While the invention has been shown and described with reference to certain embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. However, it should be understood that such modifications are within the technical scope of the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

Claims (9)

A lower electrode;
A dielectric layer formed on the lower electrode, the dielectric layer including titanium oxide of rutile structure; And
And an upper electrode formed on the dielectric layer,
Wherein the lower electrode or the upper electrode has a compound in which ruthenium oxide (RuO ₂ ) having rutile structure and tin dioxide (SnO ₂ ) are formed in a ratio of 5: 1 to 6: 1.
delete The method according to claim 1,
Wherein the upper electrode or the lower electrode comprises:
Wherein at least one of fluorine (F), tantalum (Ta), antimony (Sb), and niobium (Nb) is doped.
The method according to claim 1,
Wherein the semiconductor memory element is a DRAM capacitor.
delete Forming a lower electrode on the substrate;
Forming a dielectric layer containing titanium oxide of rutile structure on the lower electrode; And
And forming an upper electrode on the dielectric layer,
Wherein the lower electrode or the upper electrode has a compound in which ruthenium oxide (RuO ₂ ) having rutile structure and tin dioxide (SnO ₂ ) are formed in a ratio of 5: 1 to 6: 1.
The method according to claim 6,
The step of forming the lower electrode or the step of forming the upper electrode may include:
(ALD), E-beam evaporation, thermal evaporation, Molecular Beam Epitaxy, Pulsed Laser Deposition (PLD), and Chemical Vapor Deposition (CVD). Wherein at least one of ruthenium oxide (RuO ₂ ) and tin dioxide (SnO ₂ ) compound layer is formed.
The method according to claim 6,
The step of forming the lower electrode or the step of forming the upper electrode may include:
Further comprising doping at least one of fluorine (F), tantalum (Ta), antimony (Sb), and niobium (Nb) in the tin dioxide.
delete

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