KR101386135B1 - Manufacturing method for decreasing interface states of sic/sio2 interface - Google Patents

Manufacturing method for decreasing interface states of sic/sio2 interface Download PDF

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KR101386135B1
KR101386135B1 KR1020120137269A KR20120137269A KR101386135B1 KR 101386135 B1 KR101386135 B1 KR 101386135B1 KR 1020120137269 A KR1020120137269 A KR 1020120137269A KR 20120137269 A KR20120137269 A KR 20120137269A KR 101386135 B1 KR101386135 B1 KR 101386135B1
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South Korea
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sic
sio
interface
plasma
film
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KR1020120137269A
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Korean (ko)
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주성재
강인호
김상철
나문경
문정현
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한국전기연구원
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02107—Forming insulating materials on a substrate
    • H01L21/02109—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates
    • H01L21/02112—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer
    • H01L21/02123—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing silicon
    • H01L21/02164—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing silicon the material being a silicon oxide, e.g. SiO2
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02107—Forming insulating materials on a substrate
    • H01L21/02225—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer
    • H01L21/0226—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process
    • H01L21/02263—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process deposition from the gas or vapour phase
    • H01L21/02271—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process deposition from the gas or vapour phase deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition
    • H01L21/02277—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process deposition from the gas or vapour phase deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition the reactions being activated by other means than plasma or thermal, e.g. photo-CVD
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02367—Substrates
    • H01L21/0237—Materials
    • H01L21/02373—Group 14 semiconducting materials
    • H01L21/02378—Silicon carbide

Abstract

The present invention relates to a SiC device manufacturing method with decreased interface states of SiC and SiO_2 interfaces. The SiC device manufacturing method with decreased interface states of SiC and SiO_2 interfaces, comprises a first step of disassembling gases with nitrogen atoms in the plasma state, adsorbing the resultant nitrogen atoms, nitrogen ions, or radicals with nitrogen onto an SiC surface and making the resultant components react to the SiC surface; and a second step of forming a SiO_2 film on the SiC surface after performing the first step. The SiC surface is directly treated with mixed gases including gases with nitrogen atoms in the plasma state, and the SiO_2 film is deposited on the treated SiC surface. The interface states of the SiC and SiO_2 interfaces can be favorably decreased as the molecules of the gases with nitrogen atoms are effectively divided into atoms or ions in the plasma state.

Description

Manufacturing method for decreasing interface states of SiC / SiO2 interface

The present invention SiC and SiO 2 The present invention relates to a method for manufacturing a SiC device having a reduced interface level at an interface, and more particularly, to surface treatment with a plasma of a mixed gas containing gases containing nitrogen atoms on a silicon carbide (SiC) surface, and By depositing a SiO 2 film on the surface-treated SiC, gaseous molecules of gases containing nitrogen atoms are efficiently decomposed into atoms or ions in a plasma state and projected directly onto the surface of SiC so that SiC and SiO 2 SiC and SiO 2 reduce the interface level at the interface The present invention relates to a method for manufacturing a SiC device having reduced interface level at an interface.

Generally, silicon carbide (SiC) is used in various devices such as power semiconductors and semiconductor sensors.

In order to manufacture and use the SiC device, it is necessary to reduce the interface states of the SiC / SiO 2 interface, which is one of the main causes of deteriorating the performance and reliability of the SiC device.

In general, many defects, including dangling bonds, exist at the interface between SiC and SiO 2 , and these form an interface level to trap holes and electrons, thereby operating characteristics of the SiC device. Lowers. In addition, the SiC / SiO 2 interface where these defects exist is structurally weak, which is a critical cause of deteriorating the reliability of the SiC device, such as abnormal breakdown characteristics when a high electric field is applied.

However, in 1997, VV Afanas'ev et al. Published the international journal Physica Status Solidi (a) vol. 162 pp. According to the paper published in 321-337, “Intrinsic SiC / SiO 2 interface states,” the SiC / SiO 2 interface has a concentration of 100 times higher than that of the Si / SiO 2 interface due to its structural properties.

Therefore, the research to find a way to improve the quality of the SiC / SiO 2 interface having a fundamentally high defect density has been started for a long time in the SiC field, but has not yet secured a complete solution.

Current techniques commonly used to lower the SiC / SiO 2 interfacial level are described in pp. 705-745 of the book “SiC Materials and Devices volume 1,” edited by M. Shur, S. Rumyantsev, and M. Levinshtein. As summarized by G. Pensl et al. In the published “SiC Material Properties,” (1) Nitriding of SiO 2 films at temperatures higher than 1000 ° C using gases such as NO, N 2 O, and NH 3 in a furnace; Alternatively, (2) or a method in which nitrogen atoms are ion-implanted on the SiC surface in advance very shallowly and then SiC is oxidized at a high temperature to form an SiO 2 oxide film so that the nitrogen atoms are positioned at the SiC / SiO 2 interface.

The core concept of both methods is described by K. McDonald et al. In Journal of Applied Physics vol.93, pp. As presented in the paper "Characterization and modeling of the nitrogen passivation of interface traps in SiO 2 / 4H-SiC" published in 2719-2722, nitrogen atoms act on defects at the SiC / SiO 2 interface, such as broken bonds. It is a principle to reduce the interface level by forming stable covalent bonds such as C≡N and Si≡N.

However, the high temperature nitriding method of the above method has a problem that the process is inefficient because of the high temperature, and the ion implantation method requires the use of an ultra-expensive process equipment such as nitrogen ion implantation.

Accordingly, the present invention has been made to solve the above problems of the prior art, the surface of the silicon carbide (SiC) surface of the mixed gas containing a gas containing nitrogen atoms directly to the surface treatment, plasma surface treatment By depositing a SiO 2 film on SiC, the gas molecules of gases containing nitrogen atoms are efficiently decomposed into atoms or ions in a plasma state and are projected directly onto the surface of SiC so that SiC and SiO 2 SiC and SiO 2 reduce the interface level at the interface It is an object of the present invention to provide a method for manufacturing a SiC device having an reduced interface level at an interface.

The present invention for achieving the above object, SiC and SiO 2 In the method for manufacturing a SiC device having a reduced interfacial level at an interface, a surface containing a nitrogen atom, a nitrogen ion, or a radical containing nitrogen is decomposed in a plasma state by decomposing a gas containing nitrogen atoms in a plasma state. Adsorbing and reacting with the first step; A second step of forming a SiO 2 film on a SiC surface after the first step; and including SiC and SiO 2 The manufacturing method of the SiC element which reduced the interface level of an interface is made into a technical subject matter.

The gas containing the nitrogen atom is NO, N 2 O, N 2 , NH 3 One or more of the .

The SiO 2 film formation in the second step is preferably formed by plasma chemical vapor deposition (PECVD).

After the SiO 2 film is formed in the second step, heat treatment is preferably performed at a temperature of 1000 ° C. to 2000 ° C.

Accordingly, the surface of the silicon carbide (SiC) is directly surface-treated with a plasma of a mixed gas containing gases containing nitrogen atoms, and by depositing a SiO 2 film on the surface-treated SiC, containing nitrogen atoms is the gas molecules of the gas are decomposed efficiently by atoms or ions in a plasma state directly incident on the SiC surface of SiC and SiO 2, which There is an advantage of reducing the interface level of the interface.

According to the present invention, the interface level of the SiC / SiO 2 interface can be reduced, so that the operating characteristics and reliability of the SiC power semiconductor device (for example, SiC MOSFET) and the SiC semiconductor sensor are improved.

In addition, since gas molecules such as NO, N 2 O, N 2 , and NH 3 are efficiently decomposed into atoms or ions in a plasma state and projected directly onto the surface of SiC, the process proceeds more efficiently at a lower temperature than the high temperature nitriding method in the prior art. In addition, there is an effect that there is no need to use a very expensive process equipment, such as nitrogen ion implantation in the prior art.

1 is a surface of the SiC according to the present invention pretreated with N 2 O plasma for 1 hour, and then deposited with an oxide film by plasma-enhanced chemical vapor deposition (PECVD) using SiH 4 and N 2 O A diagram showing the results of secondary ion mass spectrometry (SIMS) analysis of the specimen,
FIG. 2 shows the concentration distribution of interface states extracted by capacitance-voltage (CV) measurement for SiC specimens deposited with PECVD using SiH 4 and N 2 O without N 2 O plasma pretreatment. Is shown,
Figure 3 shows the concentration distribution of the interface state applying the N 2 O plasma pre-treatment according to the present invention, by using SiH 4 and N 2 O, extracted with capacitance-voltage (CV) measurement with respect to the SiC specimen depositing a PECVD oxide It is also.

Hereinafter, preferred embodiments of the present invention will be described in detail.

1 is a surface of the SiC according to the present invention pretreated with N 2 O plasma for 1 hour, and then deposited with an oxide film by plasma-enhanced chemical vapor deposition (PECVD) using SiH 4 and N 2 O secondary ion mass spectrometry of the sample (secondary ion mass spectrometry: SIMS) is a diagram showing an analysis result 2 is N 2 O which does not apply the plasma pre-treatment by using SiH 4 and N 2 O depositing an oxide film by PECVD SiC specimens Figure 3 shows the concentration distribution of the interface states extracted by capacitance-voltage (CV) measurement, and FIG. 3 is a N 2 O plasma pretreatment according to the present invention, using SiH 4 and N 2 O The concentration distribution of the interface level extracted by the capacitance-voltage (CV) measurement method for the SiC specimens on which the PECVD oxide film was deposited.

As shown, the present invention suggests that in addition to the two prior arts mentioned above, there is a third method for placing nitrogen atoms at the SiC / SiO 2 interface.

That is, the surface treatment is carried out directly with a plasma of a gas containing nitrogen atoms on the surface of the SiC, for example, gases such as NO, N 2 O, N 2 , NH 3 , and the like. The SiO 2 film is formed on the SiC by deposition or oxidation.

According to this method, since gas molecules such as NO, N 2 O, N 2 , and NH 3 are efficiently decomposed into atoms or ions in a plasma state and projected directly onto the surface of SiC, in the prior art, it is much more efficient at low temperature than in high temperature nitriding. The process proceeds, and there is no need to use an extremely expensive process equipment such as nitrogen ion implantation in the prior art.

According to the present invention, the nitriding process of the SiC / SiO 2 interface proceeds in the following two steps.

First step:

Plasma treatment is performed while the SiC surface is exposed to allow nitrogen atoms to adsorb and react on the SiC surface. In the plasma treatment, gases containing nitrogen atoms, for example, NO, N 2 O, N 2 , NH 3 , and the like, and an inert gas such as Ar, He, Ne, or the like is added as an auxiliary gas. It is preferable to use.

In the plasma treatment, when the plasma directly contacts the SiC surface, the SiC surface damage may occur due to high energy ions. Therefore, it is preferable to use a remote plasma plasma apparatus. This remote plasma nitridation (RPN) was first studied and applied in the silicon ultra-high integrated circuit (ULSI) process of less than 100 nm in the design rule, but in the silicon ULSI process, SiO 2 film is already formed on the silicon. Although the RPN process is used to prevent nitrogen atoms from diffusing at the Si / SiO 2 interface in the state, that is, the nitrogen is mainly located far from the interface even in SiO 2 , in the present invention, the SiO 2 film is not yet formed in the SiC. The opposite of concept and purpose is that the RPN process is used to concentrate nitrogen where possible at the SiC / SiO 2 interface.

In addition, the process temperature of the plasma treatment step is preferably maintained at 500 ℃ or less.

Second step:

An SiO 2 film is formed on the SiC immediately after the plasma treatment process is completed. The SiO 2 film may be formed by a deposition process or an oxidation process, but it is preferable to form the SiO 2 film by a deposition process at a temperature of 500 ° C. or less so as to prevent desorption of nitrogen atoms adsorbed and reacted on the surface in the first step. .

Chemical vapor deposition (CVD) is preferably used for the SiO 2 deposition process, and plasma chemical vapor deposition (PECVD) is preferably used to lower the deposition temperature to 500 ° C. or lower. In particular, in the case of using the plasma chemical vapor deposition method, there is an advantage in that the plasma treatment process of the first step and the SiO 2 deposition process of the second step can be continuously performed by changing only the gas used without breaking the vacuum in the same equipment.

In the SiO 2 deposition process using plasma chemical vapor deposition, it is preferable to use a remote plasma device for the same reason as in the first step.

After forming the SiO 2 film, it is preferable to perform a high temperature heat treatment of 1000 ° C. or higher in a nitrogen or oxygen atmosphere in order to improve the SiC / SiO 2 interfacial properties.

In order to explain the method described above in more detail, the present embodiment and the results are actually described. This embodiment is only one example of implementing the concepts presented in the present invention, but the core idea of the present invention is not limited thereto.

 <Examples>

First step:

The 4H-SiC substrate is washed with sulfuric acid, hydrochloric acid, etc. and finally immersed in a solution containing hydrofluoric acid (HF) to completely remove the native oxide on the SiC substrate. The SiC substrate is placed in a parallel-plate type PECVD apparatus and the temperature of the SiC substrate is heated to 400 ° C. while pumping until the base pressure is about 5 × 10 −6 Torr or less. When the base pressure is reached, 600 sccm of N 2 O gas is introduced into the chamber to form a process pressure of about 500 mTorr, and an N 2 O plasma is generated by applying RF power of 300 W and plasma treatment is performed on the SiC substrate for 1 hour. do.

Second step:

Immediately after completion of the N 2 O plasma treatment for 1 hour, 8 sccm of SiH 4 and 600 sccm of N 2 O were introduced into the chamber to form a process pressure of about 500 mTorr, and RF power of 300 W was maintained. Apply to generate a plasma and continue for about 4 minutes to deposit about 70 nm of SiO 2 film onto the SiC substrate. After the deposition of SiO 2 , the SiC substrate was removed from PECVD, immediately placed in an oxidation furnace, an oxygen atmosphere was formed, and heat-treated at 1150 ° C. for 5 hours.

1 is a result of analyzing by secondary ion mass spectrometry (SIMS) after the process as in the above embodiment, it can be seen that a large amount of nitrogen is detected at the SiC / SiO 2 interface.

In addition, capacitance-voltage interface state is distributed as shown in Figure 2 for a SiC substrate deposited SiO 2 film with a PECVD (CV) when an interface state measured by the measuring method without the N 2 O plasma treatment to the SiC surface, but, N 2 O plasma In the case of the treatment, it can be seen that the interface level decreases as shown in FIG. 3.

Claims (4)

In the method for manufacturing a SiC device having a reduced interfacial level between an SiC and SiO 2 interface, a nitrogen atom, a nitrogen ion, or a radical containing nitrogen generated from the decomposition of a gas containing nitrogen atoms in a plasma state (radical) ) Adsorbing and reacting Si) on the SiC surface; And a second step of forming a SiO 2 film on the SiC surface after the first step.
The nitrogen-containing gas is a method of manufacturing a SiC device is reduced the interface level of the SiC and SiO 2 interface, characterized in that at least one of NO, N 2 O, N 2 , NH 3 is used. delete According to claim 1, SiO 2 film formed in the second step is a process for producing a SiC element of SiC and SiO 2 interface interface state is reduced as to form a plasma enhanced chemical vapor deposition (PECVD). The SiC and SiO 2 of claim 3, wherein after the SiO 2 film is formed in the second step, heat treatment is performed at a temperature of 1000 ° C. to 2000 ° C. 5. A method for manufacturing a SiC device with reduced interface level at the interface.
KR1020120137269A 2012-11-29 2012-11-29 Manufacturing method for decreasing interface states of sic/sio2 interface KR101386135B1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115784774A (en) * 2023-02-06 2023-03-14 江苏邑文微电子科技有限公司 Method for improving interface characteristics of SiC Mos

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR940008566B1 (en) * 1990-05-28 1994-09-24 가부시키가이샤 도시바 Manufacturing method of semiconductor device
KR19980024396A (en) * 1996-09-06 1998-07-06 추후 Thin film fabrication method and apparatus and semiconductor device with semiconductor-insulator junction structure
KR20020037447A (en) * 2000-11-14 2002-05-21 추후제출 SiC SEMICONDUCTOR DEVICE
KR20050024244A (en) * 2003-09-03 2005-03-10 닛본 에이. 에스. 엠 가부시끼가이샤 Method of forming a thin film

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR940008566B1 (en) * 1990-05-28 1994-09-24 가부시키가이샤 도시바 Manufacturing method of semiconductor device
KR19980024396A (en) * 1996-09-06 1998-07-06 추후 Thin film fabrication method and apparatus and semiconductor device with semiconductor-insulator junction structure
KR20020037447A (en) * 2000-11-14 2002-05-21 추후제출 SiC SEMICONDUCTOR DEVICE
KR20050024244A (en) * 2003-09-03 2005-03-10 닛본 에이. 에스. 엠 가부시끼가이샤 Method of forming a thin film

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115784774A (en) * 2023-02-06 2023-03-14 江苏邑文微电子科技有限公司 Method for improving interface characteristics of SiC Mos
CN115784774B (en) * 2023-02-06 2023-04-25 江苏邑文微电子科技有限公司 Method for improving SiC Mos interface characteristics

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