JPH0574762A - Formation of insulating film - Google Patents
Formation of insulating filmInfo
- Publication number
- JPH0574762A JPH0574762A JP23520291A JP23520291A JPH0574762A JP H0574762 A JPH0574762 A JP H0574762A JP 23520291 A JP23520291 A JP 23520291A JP 23520291 A JP23520291 A JP 23520291A JP H0574762 A JPH0574762 A JP H0574762A
- Authority
- JP
- Japan
- Prior art keywords
- substrate
- insulating film
- oxide film
- silicon
- nitrogen
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 230000015572 biosynthetic process Effects 0.000 title abstract description 6
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical group [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 29
- IJGRMHOSHXDMSA-UHFFFAOYSA-N nitrogen Substances N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 29
- 238000000034 method Methods 0.000 claims abstract description 25
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 15
- 238000006243 chemical reaction Methods 0.000 claims abstract description 14
- 125000001153 fluoro group Chemical group F* 0.000 claims abstract description 6
- 239000007789 gas Substances 0.000 claims description 32
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 25
- 229910052710 silicon Inorganic materials 0.000 claims description 22
- 239000010703 silicon Substances 0.000 claims description 22
- 230000001590 oxidative effect Effects 0.000 claims description 14
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 9
- 239000001301 oxygen Substances 0.000 claims description 9
- 229910052760 oxygen Inorganic materials 0.000 claims description 9
- 229910052814 silicon oxide Inorganic materials 0.000 claims description 9
- 238000010438 heat treatment Methods 0.000 claims description 5
- 238000004140 cleaning Methods 0.000 claims description 4
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 3
- 239000000758 substrate Substances 0.000 abstract description 42
- 230000003647 oxidation Effects 0.000 abstract description 20
- 238000007254 oxidation reaction Methods 0.000 abstract description 20
- 125000004429 atom Chemical group 0.000 abstract description 8
- 229910052731 fluorine Inorganic materials 0.000 abstract description 8
- 239000011737 fluorine Substances 0.000 abstract description 8
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 abstract description 5
- 229910001882 dioxygen Inorganic materials 0.000 abstract description 5
- 230000015556 catabolic process Effects 0.000 abstract description 4
- 150000002500 ions Chemical class 0.000 abstract description 4
- -1 nitrogen ions Chemical class 0.000 abstract description 4
- 229910007991 Si-N Inorganic materials 0.000 abstract description 2
- 229910006294 Si—N Inorganic materials 0.000 abstract description 2
- 239000010408 film Substances 0.000 description 73
- 239000010453 quartz Substances 0.000 description 16
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 7
- 125000004433 nitrogen atom Chemical group N* 0.000 description 7
- 238000005468 ion implantation Methods 0.000 description 6
- 229910001873 dinitrogen Inorganic materials 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 229910003849 O-Si Inorganic materials 0.000 description 3
- 229910003872 O—Si Inorganic materials 0.000 description 3
- 238000010790 dilution Methods 0.000 description 3
- 239000012895 dilution Substances 0.000 description 3
- 230000005669 field effect Effects 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- GQPLMRYTRLFLPF-UHFFFAOYSA-N Nitrous Oxide Chemical compound [O-][N+]#N GQPLMRYTRLFLPF-UHFFFAOYSA-N 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 239000002784 hot electron Substances 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229910018557 Si O Inorganic materials 0.000 description 1
- 229910008045 Si-Si Inorganic materials 0.000 description 1
- 229910002808 Si–O–Si Inorganic materials 0.000 description 1
- 229910008284 Si—F Inorganic materials 0.000 description 1
- 229910006411 Si—Si Inorganic materials 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- 238000002513 implantation Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 150000002829 nitrogen Chemical class 0.000 description 1
- 229960001730 nitrous oxide Drugs 0.000 description 1
- 235000013842 nitrous oxide Nutrition 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Inorganic materials [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 1
- 241000894007 species Species 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 125000004434 sulfur atom Chemical group 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000003949 trap density measurement Methods 0.000 description 1
Landscapes
- Formation Of Insulating Films (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は絶縁膜形成方法、特に
膜厚の極めて薄い絶縁膜を高品質に形成するための方法
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an insulating film, and more particularly to a method for forming an insulating film having an extremely thin film with high quality.
【０００２】[0002]
【従来の技術】最先端技術により形成されるシリコン集
積回路、特にＭＯＳ（Ｍｅｔａｌ Ｏｘｉｄｅ Ｓｅｍ
ｉｃｏｎｄｕｃｔｏｒ）集積回路では膜厚が極めて薄い
酸化膜がゲート絶縁膜に用いられる。とりわけ１．０μ
ｍ以下のゲート長を有するサブミクロンＭＯＳデバイス
では膜厚が例えば１００オングストローム（以下、オン
グストロームをＡ°の記号で示す場合がある）以下とな
る酸化膜が用いられ、このように膜厚を薄くすることに
よって利得の向上を図っている。2. Description of the Related Art Silicon integrated circuits formed by the latest technology, especially MOS (Metal Oxide Sem)
In an integrated circuit, an oxide film having an extremely thin film thickness is used as a gate insulating film. Especially 1.0μ
In a submicron MOS device having a gate length of m or less, an oxide film having a film thickness of, for example, 100 angstrom (hereinafter, angstrom may be indicated by a symbol of A °) or less is used, and the film thickness is reduced in this way. By doing so, the gain is improved.
【０００３】酸化膜の形成は、例えば文献：「ＶＬＳＩ
製造技術、徳山 巍、橋本 哲一編著、日経ＢＰ社、
Ｐ．８３（１９８９）」に示されるように、従来、次の
ようにして行われる。The formation of an oxide film is described, for example, in the document: "VLSI.
Manufacturing technology, Shiba Tokuyama, Tetsuichi Hashimoto, Nikkei BP,
P. 83 (1989) ”, is conventionally performed as follows.
【０００４】この文献に開示されている方法では、先
ず、電気炉によって８００℃〜１２００℃に加熱した石
英管内に、清浄化した基板を配置する。その後、酸化膜
形成のための酸化性ガスを石英管内に導入する。酸化性
ガスとしては例えば、乾燥した酸素ガス、或いは酸素お
よび水素の混合ガス、或いは塩酸を霧状にして酸素ガス
と混合したガスを用いる。酸化性ガスを導入した石英管
内に、形成しようとする膜厚に見合った一定時間、一定
温度で基板を放置して酸化膜を連続成長させることによ
って、均一な膜厚の酸化膜を基板表面に形成している。In the method disclosed in this document, first, a cleaned substrate is placed in a quartz tube heated to 800 to 1200 ° C. by an electric furnace. Then, an oxidizing gas for forming an oxide film is introduced into the quartz tube. As the oxidizing gas, for example, a dry oxygen gas, a mixed gas of oxygen and hydrogen, or a gas in which hydrochloric acid is atomized and mixed with the oxygen gas is used. An oxide film with a uniform thickness is formed on the substrate surface by allowing the substrate to stand for a certain period of time corresponding to the film thickness to be formed at a constant temperature and continuously growing the oxide film in a quartz tube into which an oxidizing gas has been introduced. Is forming.
【０００５】[0005]
【発明が解決しようとする課題】しかしながら、以上に
述べた酸化膜形成方法では、酸化膜を休みなく連続成長
させているので、例えば、１００Ａ°以下の薄い酸化膜
を形成する場合、その膜厚を制御するのが困難であっ
た。そのため、このような薄い酸化膜を形成する場合、
その膜厚制御を行うためには、９００℃以下に酸化温度
を下げて酸化速度を下げる（以下、これを低温酸化法と
称することもある）か、或いは窒素で酸素を希釈して酸
化速度を下げて行う方法（以下、これを希釈酸化法と称
することもある）をとっていた。However, in the above-described oxide film forming method, since the oxide film is continuously grown without a break, for example, when a thin oxide film of 100 A ° or less is formed, its film thickness is reduced. Was difficult to control. Therefore, when forming such a thin oxide film,
In order to control the film thickness, the oxidation temperature is lowered to 900 ° C. or lower to reduce the oxidation rate (hereinafter, this may be referred to as a low temperature oxidation method), or oxygen is diluted with nitrogen to reduce the oxidation rate. A method of lowering the temperature (hereinafter, this may be referred to as a dilution oxidation method) has been adopted.
【０００６】しかしながら、低温酸化法ではシリコン酸
化膜／シリコン（基板）界面が数十Ａ°のオーダで、シ
リコンの突起や界面のうねりが発生し、そのため、絶縁
耐圧の低下を招くという問題があった。一方、希釈酸化
法の場合では、一般に１０００℃以上の高温で長時間熱
処理を行うため、不純物の再分布が生じ、不純物の分布
が設計通りにならない等の問題があった。それ故、上述
のいずれの方法を行っても、薄い酸化膜の絶縁破壊耐性
等の膜質自体の向上は望めなかった。However, in the low-temperature oxidation method, there is a problem that the silicon oxide film / silicon (substrate) interface has an order of several tens A ° and silicon protrusions and interface undulations occur, which lowers the dielectric strength voltage. It was On the other hand, in the case of the dilution oxidation method, since heat treatment is generally performed at a high temperature of 1000 ° C. or higher for a long time, redistribution of impurities occurs, and there is a problem that the distribution of impurities does not become as designed. Therefore, no improvement in the film quality itself such as the dielectric breakdown resistance of the thin oxide film could be expected even if any of the above methods was performed.
【０００７】また、これらの低温酸化法、希釈酸化法に
より得られる酸化膜は一般に緻密ではなく、シリコン／
シリコン酸化膜界面や、酸化膜中に原子の不安定の結合
状態、例えば、未結合手やシリコン原子の不対結合や、
弱い結合を含むＳｉ−Ｓｉ結合、Ｓｉ−Ｏ結合、Ｏ−Ｏ
結合、或いは歪んだＳｉ−Ｏ−Ｓｉ結合が多く存在する
非結晶構造となっているため、そもそも界面準位（Ｄｉ
ｔ）が高くなって、トラップ密度が増加する傾向があっ
た。このように形成された酸化膜を、ＭＯＳ型電界効果
トランジスタのゲート酸化膜として使用する場合、上記
の現象に起因して種々の問題が生じている。例えば、ゲ
ート長１．０μｍ以下の微細ＭＯＳ型電界効果トランジ
スタにおいては、チャネル領域で発生したホットエレク
トロンが酸化膜中に侵入した場合、電子はこのようなシ
リコン原子の不対結合や、歪んだＳｉ−Ｏ−Ｓｉ結合等
にトラップされ、新たな界面準位を発生させ、そのため
ＭＯＳ型トランジスタにおける閾値電圧の変動や、伝達
コンダクタンスの低下を引き起こすという問題が生じ
る。Further, the oxide film obtained by these low temperature oxidation method and dilution oxidation method is generally not dense and is
An unstable bond state of atoms in the silicon oxide film interface or the oxide film, for example, dangling bonds or unpaired bonds of silicon atoms,
Si-Si bond including weak bond, Si-O bond, OO
Because of the amorphous structure in which many bonds or distorted Si-O-Si bonds exist, the interface state (Di
There was a tendency that t) became high and the trap density increased. When the oxide film thus formed is used as a gate oxide film of a MOS field effect transistor, various problems occur due to the above phenomenon. For example, in a fine MOS field-effect transistor having a gate length of 1.0 μm or less, when hot electrons generated in the channel region penetrate into the oxide film, electrons are unpaired with such silicon atoms or distorted Si. There is a problem that a new interface level is generated by being trapped by —O—Si bond or the like, which causes a change in threshold voltage and a decrease in transfer conductance in the MOS transistor.
【０００８】また、このようにして形成された酸化膜を
用いてＭＯＳ構造を構成し、このＭＯＳ構造の耐圧試験
を行うと、酸化膜中のシリコン原子の不対結合や歪んだ
Ｓｉ−Ｏ−Ｓｉ結合等のような結合が切れることによ
り、新たなトラップが当該酸化膜中に発生し、このトラ
ップが絶縁破壊の原因となる。Further, when a MOS structure is formed by using the oxide film thus formed and a withstand voltage test of this MOS structure is performed, unpaired bonds of silicon atoms in the oxide film and distorted Si--O-- When a bond such as Si bond is broken, a new trap is generated in the oxide film, and this trap causes dielectric breakdown.
【０００９】この発明は、上述した従来の問題点に鑑み
なされたものであり、従って、この発明の目的は、絶縁
膜形成中に生じる不安定な結合手等に起因する膜欠陥を
低減して膜質の優れた薄い絶縁膜を形成できる、絶縁膜
形成方法を提供することにある。The present invention has been made in view of the above-mentioned conventional problems. Therefore, an object of the present invention is to reduce film defects caused by an unstable bond or the like generated during the formation of an insulating film. An object of the present invention is to provide an insulating film forming method capable of forming a thin insulating film having excellent film quality.
【００１０】[0010]
【課題を解決するための手段】この目的の達成を図るた
め、この発明によれば、反応炉内でシリコンの下地に対
し酸化性ガス雰囲気中で加熱処理を行って該下地に絶縁
膜を形成するに当り、シリコンの下地を清浄化する工程
と、清浄化済みの下地に窒素およびフッ素の双方または
いずれか一方の原子をイオン注入して、この下地中の表
面領域にイオン注入層を形成する工程と、前述の反応炉
内で、このイオン注入層の形成済みの下地の表面領域
を、酸化性ガス雰囲気中で、加熱処理を行って、絶縁膜
としてのシリコンの酸化膜を形成する工程とを含むこと
を特徴とする。In order to achieve this object, according to the present invention, an underlayer of silicon is heated in a reaction furnace in an oxidizing gas atmosphere to form an insulating film on the underlayer. In doing so, the step of cleaning the silicon underlayer and the ion implantation of nitrogen and / or fluorine atoms into the cleaned underlayer to form an ion-implanted layer in the surface region of this underlayer And a step of forming a silicon oxide film as an insulating film by heat-treating the surface region of the underlying layer on which the ion-implanted layer has been formed in the reaction furnace in an oxidizing gas atmosphere. It is characterized by including.
【００１１】この発明の実施に当たり、好ましくは、シ
リコンの酸化膜をＳｉＯ2 膜とするのが良い。In carrying out the present invention, it is preferable that the silicon oxide film is a SiO 2 film.
【００１２】また、この発明の好適実施例によれば、酸
化性ガス雰囲気を少なくとも酸素（Ｏ2 ）を含むガスと
するのが良い。According to the preferred embodiment of the present invention, the oxidizing gas atmosphere is preferably a gas containing at least oxygen (O 2 ).
【００１３】尚、ここでシリコンの下地とは、シリコン
基板はもとより、その他に、このシリコン基板にエピタ
キシャル層を形成したもの、その他、これらに限らず基
板やエピタキシャル層に素子が作り込まれている中間体
等、絶縁膜が形成されるべき広く下地を意味している。Here, the term "silicon underlayer" means not only a silicon substrate but also an epitaxial layer formed on the silicon substrate, and other elements such as a substrate or an epitaxial layer. It widely means a base on which an insulating film should be formed, such as an intermediate.
【００１４】[0014]
【作用】上述したこの発明の絶縁膜形成方法によれば、
シリコンの下地を清浄化した後、下地に窒素およびフッ
素の双方またはいずれか一方の元素をイオン注入して下
地中にイオン注入層を形成し、続いて、反応炉中で酸化
性ガスを用いて下地を加熱処理することによって、下地
に上にシリコンの絶縁膜を形成する。According to the insulating film forming method of the present invention described above,
After cleaning the silicon substrate, nitrogen and / or fluorine elements are ion-implanted into the substrate to form an ion-implanted layer in the substrate, followed by oxidizing gas in a reaction furnace. By heating the base, a silicon insulating film is formed on the base.
【００１５】従って、酸化中に注入した原子のうち数原
子％が酸化膜中、および、酸化膜／残存シリコン層界面
に、とり込まれる。このため、これらとり込まれた原子
が、この界面近傍のシリコン原子の不対結合や歪んだＳ
ｉ−Ｏ−Ｓｉ結合等のような未結合等に作用して、安定
したＳｉ−Ｎ結合やＳｉ−Ｆ結合や、Ｏ−Ｎ結合を形成
する。その結果、未結合手や、弱い結合が低減されるの
で、酸化膜の絶縁破壊特性の向上が図れ、従って、高品
質の膜が得られる。Therefore, a few atom% of the atoms injected during the oxidation are taken into the oxide film and the oxide film / remaining silicon layer interface. For this reason, these incorporated atoms may cause unpaired bonds of silicon atoms in the vicinity of this interface or distorted S atoms.
It acts on unbonded bonds such as i-O-Si bonds to form stable Si-N bonds, Si-F bonds, and O-N bonds. As a result, dangling bonds and weak bonds are reduced, so that the dielectric breakdown characteristics of the oxide film can be improved, and thus a high quality film can be obtained.
【００１６】[0016]
【実施例】以下、図面を参照し、この出願の発明の実施
例につき説明する。Embodiments of the invention of this application will be described below with reference to the drawings.
【００１７】尚、図面は発明が理解出来る程度に、各構
成成分の寸法、形状および配設位置を概略的に示してい
るにすぎない。また、以下の説明では、特定の材料およ
び特定の数値的条件を挙げて説明するが、これら材料お
よび条件は単なる好適例にすぎず、従ってこれらに何ら
限定されるものではない。It should be noted that the drawings merely schematically show the dimensions, shapes, and positions of the constituent components so that the invention can be understood. Further, in the following description, specific materials and specific numerical conditions will be described, but these materials and conditions are merely preferable examples and are not limited to these.
【００１８】先ず、この発明の方法の説明に入る前に、
この発明を実施するための装置につき簡単に説明する。First, before entering the description of the method of the present invention,
A device for carrying out the present invention will be briefly described.
【００１９】図２は、この発明の実施に用いる、従来周
知の構造の反応炉を概略的に示す図である。この反応炉
の構成につき簡単に説明する。この反応炉は、主とし
て、石英管１２と、その一端側に封入したガス導入管１
４と、石英管１２の他端の開放端に開閉自在に取りつけ
た扉１６と、この開放端側に設けたガス排気管１８とを
具えている。そして、石英管１２の中間の、外周壁に加
熱ヒータ２０を設けてある。FIG. 2 is a diagram schematically showing a reactor having a conventionally well-known structure used for carrying out the present invention. The structure of this reaction furnace will be briefly described. This reactor is mainly composed of a quartz tube 12 and a gas introduction tube 1 enclosed at one end thereof.
4, a quartz pipe 12, a door 16 openably and closably attached to the open end of the other end, and a gas exhaust pipe 18 provided on the open end side. A heater 20 is provided on the outer peripheral wall in the middle of the quartz tube 12.
【００２０】この石英管１２内に石英ボート２２を出し
入れ自在に設けてあり、この石英ボート２２には、被処
理対象物２４を搭載させてある。A quartz boat 22 is provided in the quartz tube 12 so as to be freely taken in and out, and an object 24 to be processed is mounted on the quartz boat 22.
【００２１】以下、図１および図２を参照し、この装置
を用いて成膜する例につき説明する。図１は、この発明
の製造工程の一実施例を説明するための工程図であり、
各図は、この工程の主要段階で得られた構造体を、下地
の厚み方向の断面で示した図である。An example of film formation using this apparatus will be described below with reference to FIGS. 1 and 2. FIG. 1 is a process chart for explaining one embodiment of the manufacturing process of the present invention,
Each drawing is a view showing the cross section in the thickness direction of the underlayer of the structure obtained in the main stage of this process.
【００２２】この発明における実施例では、下地として
例えばシリコン基板を用意し、前処理として従来行われ
ている如く、化学薬品、純水等を用いて基板１８の洗浄
を行なう。この前処理によって自然酸化膜が除去され
た、清浄な基板表面を持ったシリコン（Ｓｉ）基板３０
を得る（図１の（Ａ））。In the embodiment of the present invention, for example, a silicon substrate is prepared as a base, and the substrate 18 is washed with chemicals, pure water or the like as a conventional pretreatment. A silicon (Si) substrate 30 having a clean substrate surface from which the natural oxide film has been removed by this pretreatment.
Is obtained ((A) of FIG. 1).
【００２３】次に、従来用いられている適当なイオン注
入装置を用いて、この基板３０に対しイオン注入を行な
う。この場合、使用するイオンを、窒素（Ｎ）およびフ
ッ素（Ｆ）の双方またはいずれか一方の原子とする。そ
して、例えば、イオン種を窒素原子とする場合、イオン
の加速エネルギーを５０ｅＶ程度とし、ドーズ量を１×
１０17（１０の１７乗）／ｃｍ2 （ｃｍの２乗）程度と
した条件で、イオン注入を行なう。この注入により、基
板３０の表面から深さ約０．１μｍのところまでの領域
に、イオン注入層３２を形成する。そして、この実施例
では、この窒素原子の基板３４への導入する濃度を、最
少でも、１×１０19（１０の１９乗）／ｃｍ3 （ｃｍの
３乗）とする。このようにして得られた構造体を図１の
（Ｂ）に示す。なお、このイオン注入層３２以外の、残
存しているＳｉ領域を３４で示し、ここではこれを残存
Ｓｉ基板と称し、また、窒素イオンの導入済みＳｉ基板
を図中３６で示す。Next, the substrate 30 is ion-implanted by using an appropriate ion-implantation device conventionally used. In this case, the ions used are atoms of nitrogen (N) and / or fluorine (F). Then, for example, when the ion species is a nitrogen atom, the acceleration energy of the ions is about 50 eV, and the dose amount is 1 ×.
Ion implantation is performed under the condition of about 10 17 (10 17 power) / cm 2 (cm 2 power). By this implantation, the ion implantation layer 32 is formed in the region from the surface of the substrate 30 to a depth of about 0.1 μm. In this embodiment, the concentration of nitrogen atoms introduced into the substrate 34 is at least 1 × 10 19 (10 19th power) / cm 3 (cm 3rd power). The structure thus obtained is shown in FIG. The remaining Si region other than the ion-implanted layer 32 is indicated by 34, which is referred to as a residual Si substrate, and the nitrogen ion introduced Si substrate is indicated by 36 in the figure.
【００２４】次に、窒素導入済み基板３６を、被処理対
象物２４として石英ボート２２に例えば垂直に立てかけ
て搭載する。次に、石英管の反応炉１２の扉１４を開
き、このボート２２を反応炉１２中に搬送して、定位置
に固定する。この状態を図２に示してある。そして、反
応炉１２を適当な真空度に真空排気しながら、この基板
３６に対し熱酸化処理を行なって、絶縁膜４０としての
シリコンの酸化膜を形成する。このようにして得られた
構造体を図１の（Ｃ）に示す。Next, the nitrogen-introduced substrate 36 is mounted on the quartz boat 22 as the object 24 to be processed by vertically standing it, for example. Next, the door 14 of the quartz tube reactor 12 is opened and the boat 22 is transported into the reactor 12 and fixed in place. This state is shown in FIG. Then, while the reaction furnace 12 is evacuated to a suitable vacuum degree, the substrate 36 is subjected to thermal oxidation treatment to form a silicon oxide film as the insulating film 40. The structure thus obtained is shown in FIG.
【００２５】この酸化処理に当たり、この実施例では、
先ず、Ｓｉ基板３６を導入する前に、ガス導入管１６よ
り反応炉１２内へ窒素ガスを導入してＳｉ基板３６が不
必要な酸化を受けないように配慮する。また、同様な酸
化防止の観点から、および、Ｓｉ基板３６の反りを防止
するため、反応炉１２の温度を、例えば、４００℃〜８
００℃程度の範囲内の適当な、低温に設定しておく。次
に、Ｓｉ基板３６を搭載した石英ボート２２を反応炉１
２の定位置に挿入した後、扉１４を閉じ、一定時間、例
えば、１０分間、ガス導入管１６から窒素を流し続け
る。この窒素により、石英管１２中に流れ込んだ空気
（特に、その中に含まれる水分）を置換する。この窒素
ガスの供給停止後、反応炉１２の温度を徐々に昇温させ
て８００℃〜９５０℃にするのが好適である。また、こ
の昇温率は、基板３６に、不所望な何らかの熱的変化を
もたらさないような割合とするのが良い。好ましくは、
この昇温率を、毎分当たり５℃前後とするのが良い。次
に、ガス導入管１６を経て、酸化性ガス供給源（図示せ
ず。）からこの反応炉である石英管１２中に酸化性ガ
ス、例えば、酸素（Ｏ2 ）ガスを導入する。このガスの
流入量は、反応炉１２内の容積、形成しようとする酸化
膜の膜厚および酸化速度に見合った、適当な量とすれば
良い。この実施例では、酸素を導入して約５分間、この
基板３６のイオン注入層３２の表面に、膜厚約１００Ａ
°の酸化膜４０が形成出来るような流入量とするのが良
い。この場合、イオン注入層３２の窒素原子は、主とし
て、酸化膜４０に熱拡散すると共に、残りの窒素原子が
残存シリコン基板３４中に、拡散層４２として残存す
る。従って、この熱酸化処理によって、シリコン基板３
４上に、窒素が拡散しているＳｉＯ2 膜として絶縁膜４
０が形成される（図１の（Ｃ））。 次に、この酸化膜
４０の形成後、直ちに、酸素ガスから窒素ガスに切り換
えてガス導入管１６を経て窒素ガスを反応炉１２中に導
入し、かつ、加熱温度を毎分５℃〜１０℃程度の範囲内
の割合で降温させて、炉内の温度を室温（約２５℃）に
し、酸化処理を停止する。In this embodiment, in this oxidation treatment,
First, before introducing the Si substrate 36, a nitrogen gas is introduced into the reaction furnace 12 through the gas introduction pipe 16 so that the Si substrate 36 is not subjected to unnecessary oxidation. Further, from the same viewpoint of preventing oxidation and in order to prevent the warp of the Si substrate 36, the temperature of the reaction furnace 12 is set to, for example, 400 ° C. to 8 ° C.
The temperature is set to an appropriate low temperature within the range of about 00 ° C. Next, the quartz boat 22 on which the Si substrate 36 is mounted is attached to the reactor 1.
After the insertion into the fixed position of 2, the door 14 is closed, and nitrogen is continuously flown from the gas introduction pipe 16 for a fixed time, for example, 10 minutes. This nitrogen replaces the air (particularly the water content contained therein) flowing into the quartz tube 12. After the supply of the nitrogen gas is stopped, the temperature of the reaction furnace 12 is preferably gradually raised to 800 ° C to 950 ° C. Further, it is preferable that the rate of temperature increase is such that it does not cause any undesired thermal change on the substrate 36. Preferably,
The rate of temperature increase is preferably around 5 ° C. per minute. Next, an oxidizing gas, for example, oxygen (O 2 ) gas is introduced from the oxidizing gas supply source (not shown) into the quartz tube 12, which is the reaction furnace, through the gas introducing pipe 16. The inflow amount of this gas may be an appropriate amount corresponding to the volume in the reaction furnace 12, the thickness of the oxide film to be formed, and the oxidation rate. In this embodiment, oxygen is introduced for about 5 minutes, and a film thickness of about 100 A is formed on the surface of the ion implantation layer 32 of the substrate 36.
The inflow rate is preferably such that the oxide film 40 of 90 ° can be formed. In this case, the nitrogen atoms of the ion-implanted layer 32 are mainly thermally diffused into the oxide film 40, and the remaining nitrogen atoms remain as the diffusion layer 42 in the remaining silicon substrate 34. Therefore, by this thermal oxidation treatment, the silicon substrate 3
An insulating film 4 as a SiO 2 film in which nitrogen is diffused.
0 is formed ((C) of FIG. 1). Next, immediately after the formation of the oxide film 40, the oxygen gas is switched to the nitrogen gas, the nitrogen gas is introduced into the reaction furnace 12 through the gas introduction pipe 16, and the heating temperature is 5 ° C. to 10 ° C. per minute. The temperature is lowered at a rate within the range of about, the temperature in the furnace is brought to room temperature (about 25 ° C.), and the oxidation treatment is stopped.
【００２６】この発明は、上述した実施例のみに限られ
るものではなく、以下に説明するような種々の変更また
は変形を加えることができる。The present invention is not limited to the above-described embodiments, but various changes or modifications as described below can be added.
【００２７】上述した実施例では、注入したいオンを窒
素原子としたが、窒素原子を用いる代わりに、フッ素原
子を用いても良いし、また、両者を混合して用いても良
い。この場合、フッ素原子の基板３４への導入する濃度
を、最少でも、１×１０20（１０の２０乗）／ｃｍ
3 （ｃｍの３乗）とする。両者を併用する場合には、そ
の混合濃度を、最少でも、１×（１０19〜１０20）／ｃ
ｍ3 とすれば良い。このような値にそれぞれの濃度を設
定するのは、絶縁膜を形成する時、この絶縁膜に所要の
原子を拡散させて不所望なシリコン原子の不対結合や歪
んだ結合が発生するのを確実に抑制するためである。な
お、フッ素をイオン注入すると、フッ素を含んだシリコ
ンの酸化膜が形成出来、また、窒素とフッ素をイオン注
入した場合には、窒素とフッ素を含んだシリコンの酸化
膜が形成出来る。In the above-mentioned embodiments, nitrogen atoms are used as the ON atoms to be injected, but fluorine atoms may be used instead of nitrogen atoms, or both may be mixed and used. In this case, the concentration of fluorine atoms introduced into the substrate 34 should be at least 1 × 10 20 (10 to the power of 20) / cm.
3 (cm to the third power). When both are used together, the mixture concentration should be at least 1 × (10 19 to 10 20 ) / c.
m 3 is sufficient. The respective concentrations are set to such values so that when forming an insulating film, necessary atoms are diffused in the insulating film to cause undesired unpaired bonds and distorted bonds of silicon atoms. This is for surely suppressing. Note that when fluorine is ion-implanted, a silicon oxide film containing fluorine can be formed, and when nitrogen and fluorine are ion-implanted, a silicon oxide film containing nitrogen and fluorine can be formed.
【００２８】また、上述した実施例では酸化性ガスとし
て酸素（Ｏ2 ）ガスを用いたが、この酸素ガスの代わり
に、少なくとも酸素を含んだガス、例えば一酸化二窒素
（Ｎ2 Ｏ）ガスのような酸素を含むガスを用いても同様
に十分な酸化効果を上げることができる。Although oxygen (O 2 ) gas is used as the oxidizing gas in the above-described embodiments, a gas containing at least oxygen, such as dinitrogen monoxide (N 2 O) gas, is used instead of the oxygen gas. Even if a gas containing oxygen as described above is used, a sufficient oxidizing effect can be similarly obtained.
【００２９】また、上述した実施例では、絶縁膜の形成
前に還元ガス雰囲気中で加熱を行って下地である基板の
清浄化をしているが、所要に応じて、この処理は省いて
も勿論良い。Further, in the above-mentioned embodiment, the substrate as the base is cleaned by heating in the reducing gas atmosphere before forming the insulating film, but this process may be omitted if necessary. Of course good.
【００３０】[0030]
【発明の効果】上述した説明からも明らかなように、こ
の発明の絶縁膜形成方法によれば、シリコンの下地に、
予め、窒素およびまたはフッ素をイオン注入してから熱
酸化処理を行なっている。このため、酸化中に、数原子
％の窒素原子やフッ素原子が、絶縁膜中および絶縁膜／
シリコン基板との界面に取り込まれるため、このような
界面近傍でのシリコン原子の不対結合や、歪んだＳｉ−
Ｏ−Ｓｉ結合等といった未結合等似作用して安定なＳｉ
−Ｎ結合やＯ−Ｎ結合を形成する。このため、絶縁膜中
やおよび絶縁膜／シリコン基板の界面の未結合手や弱い
結合が低減され、よって、絶縁耐圧が著しく向上し他、
品質の優れた絶縁膜が得られる。As is apparent from the above description, according to the method for forming an insulating film of the present invention, a silicon underlayer
Nitrogen and / or fluorine are ion-implanted in advance, and then thermal oxidation treatment is performed. Therefore, during the oxidation, several atomic% of nitrogen atoms and fluorine atoms are contained in the insulating film and the insulating film /
Since it is taken into the interface with the silicon substrate, unpaired bonds of silicon atoms near the interface and strained Si-
Stable Si by similar action such as unbonding such as O-Si bond
-N bond and O-N bond are formed. Therefore, dangling bonds and weak bonds in the insulating film and at the interface between the insulating film and the silicon substrate are reduced, so that the withstand voltage is remarkably improved.
An insulating film with excellent quality can be obtained.
【００３１】従って、この発明により形成した絶縁膜を
用いて電子デバイス例えばＭＯＳ型電界効果トランジス
タを作製すると、トランジスタのチャネル領域で発生し
たホットエレクトロンはトラップされにくくなり、その
ため、従来のＭＯＳ型トランジスタで見られた閾値電圧
の変動や伝達コンダクタンスの低下が起きにくくなり、
これら電子デバイスの電気的特性と信頼性を従来よりも
向上させることができる。Therefore, when an electronic device such as a MOS field effect transistor is manufactured using the insulating film formed according to the present invention, hot electrons generated in the channel region of the transistor are less likely to be trapped. Therefore, in the conventional MOS transistor. It is difficult for the observed fluctuations in threshold voltage and reduction in transfer conductance to occur,
The electrical characteristics and reliability of these electronic devices can be improved more than ever before.
【図１】（Ａ）〜（Ｃ）は、この発明の絶縁膜形成方法
の一実施例の説明に供する工程図である。FIG. 1A to FIG. 1C are process drawings for explaining an embodiment of an insulating film forming method of the present invention.
【図２】この発明の絶縁膜形成方法の一実施例を実施す
るための装置の要部を概略的に示す断面図である。FIG. 2 is a sectional view schematically showing a main part of an apparatus for carrying out an embodiment of an insulating film forming method of the present invention.
１２：反応炉（石英管）、 １４：扉 １６：ガス導入管、 １８：ガス排気
管 ２０：加熱ヒータ、 ２２石英ボート ２４：被処理対象物 ３０：シリコンの下地（例えば、Ｓｉ基板） ３２：イオン注入層、 ３４：残存Ｓｉ
基板 ３６：イオン注入済みＳｉ基板、 ４０：絶縁膜 ４２：拡散層。12: Reactor (quartz tube), 14: Door 16: Gas introduction tube, 18: Gas exhaust tube 20: Heater, 22 Quartz boat 24: Object to be treated 30: Silicon substrate (for example, Si substrate) 32: Ion implantation layer, 34: residual Si
Substrate 36: Ion-implanted Si substrate, 40: Insulating film 42: Diffusion layer.
Claims (3)
ガス雰囲気中で加熱処理を行って該下地に絶縁膜を形成
するに当り、 シリコンの下地を清浄化する工程と、 清浄化済みの前記下地に窒素およびフッ素の双方または
いずれか一方の原子をイオン注入して、前記下地中の表
面領域にイオン注入層を形成する工程と、 前記反応炉内で、前記イオン注入層の形成済みの下地の
表面領域を、酸化性ガス雰囲気中で、加熱処理を行っ
て、絶縁膜としてのシリコンの酸化膜を形成する工程と
を含むことを特徴とする絶縁膜形成方法。1. A step of cleaning a silicon underlayer, in which a silicon underlayer is heated in an oxidizing gas atmosphere in a reaction furnace to form an insulating film on the underlayer, and a step of cleaning the silicon underlayer is performed. Nitrogen and / or fluorine atoms are ion-implanted into the base to form an ion-implanted layer in a surface region of the base, and the ion-implanted layer is already formed in the reaction furnace. And a step of forming a silicon oxide film as an insulating film by subjecting the surface region of the base to a heat treatment in an oxidizing gas atmosphere to form an insulating film.
て、前記シリコンの酸化膜をＳｉＯ2 膜としたことを特
徴とする絶縁膜形成方法。2. The insulating film forming method according to claim 1, wherein the silicon oxide film is a SiO 2 film.
て、前記酸化性ガス雰囲気を少なくとも酸素（Ｏ2 ）を
含むガスとすることを特徴とする絶縁膜形成方法。3. The insulating film forming method according to claim 1, wherein the oxidizing gas atmosphere is a gas containing at least oxygen (O 2 ).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23520291A JPH0574762A (en) | 1991-09-17 | 1991-09-17 | Formation of insulating film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23520291A JPH0574762A (en) | 1991-09-17 | 1991-09-17 | Formation of insulating film |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0574762A true JPH0574762A (en) | 1993-03-26 |
Family
ID=16982594
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23520291A Withdrawn JPH0574762A (en) | 1991-09-17 | 1991-09-17 | Formation of insulating film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0574762A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5846888A (en) * | 1996-09-27 | 1998-12-08 | Micron Technology, Inc. | Method for in-situ incorporation of desirable impurities into high pressure oxides |
| EP1052686A3 (en) * | 1999-05-14 | 2001-09-19 | Lucent Technologies Inc. | Oxidation of silicon using fluorine implants |
| EP1052685A3 (en) * | 1999-05-14 | 2001-11-07 | Lucent Technologies Inc. | Integrated circuit device having a fluorine implanted oxide layer |
| US6534380B1 (en) * | 1997-07-18 | 2003-03-18 | Denso Corporation | Semiconductor substrate and method of manufacturing the same |
| US6700170B1 (en) | 1998-12-24 | 2004-03-02 | Sharp Kabushiki Kaisha | Insulated gate transistor having a gate insulator containing nitrogen atoms and fluorine atoms |
| WO2006041069A1 (en) * | 2004-10-13 | 2006-04-20 | Shin-Etsu Handotai Co., Ltd. | Annealed wafer manufacturing method and annealed wafer |
| JP2012191086A (en) * | 2011-03-11 | 2012-10-04 | Toshiba Corp | Semiconductor device and method of manufacturing semiconductor device |
-
1991
- 1991-09-17 JP JP23520291A patent/JPH0574762A/en not_active Withdrawn
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5846888A (en) * | 1996-09-27 | 1998-12-08 | Micron Technology, Inc. | Method for in-situ incorporation of desirable impurities into high pressure oxides |
| US6534380B1 (en) * | 1997-07-18 | 2003-03-18 | Denso Corporation | Semiconductor substrate and method of manufacturing the same |
| US6700170B1 (en) | 1998-12-24 | 2004-03-02 | Sharp Kabushiki Kaisha | Insulated gate transistor having a gate insulator containing nitrogen atoms and fluorine atoms |
| EP1052686A3 (en) * | 1999-05-14 | 2001-09-19 | Lucent Technologies Inc. | Oxidation of silicon using fluorine implants |
| EP1052685A3 (en) * | 1999-05-14 | 2001-11-07 | Lucent Technologies Inc. | Integrated circuit device having a fluorine implanted oxide layer |
| US6358865B2 (en) * | 1999-05-14 | 2002-03-19 | Agere Systems Guardian Corp. | Oxidation of silicon using fluorine implant |
| WO2006041069A1 (en) * | 2004-10-13 | 2006-04-20 | Shin-Etsu Handotai Co., Ltd. | Annealed wafer manufacturing method and annealed wafer |
| JP2006114629A (en) * | 2004-10-13 | 2006-04-27 | Shin Etsu Handotai Co Ltd | Annealed wafer manufacturing method and annealed wafer |
| EP1806778A4 (en) * | 2004-10-13 | 2008-11-19 | Shinetsu Handotai Kk | METHOD FOR MANUFACTURING RECLAIMED WAFER AND RECLAIMED WAFER |
| US7659216B2 (en) | 2004-10-13 | 2010-02-09 | Shin-Etsu Handotai Co., Ltd. | Method for producing annealed wafer and annealed wafer |
| JP2012191086A (en) * | 2011-03-11 | 2012-10-04 | Toshiba Corp | Semiconductor device and method of manufacturing semiconductor device |
| US8552537B2 (en) | 2011-03-11 | 2013-10-08 | Kabushiki Kaisha Toshiba | Semiconductor device and method for fabricating the same |
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|---|---|---|---|
| A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 19981203 |