JPH0355872A - Forming method of silicon film on polycrystalline silicon film - Google Patents
Forming method of silicon film on polycrystalline silicon filmInfo
- Publication number
- JPH0355872A JPH0355872A JP19336589A JP19336589A JPH0355872A JP H0355872 A JPH0355872 A JP H0355872A JP 19336589 A JP19336589 A JP 19336589A JP 19336589 A JP19336589 A JP 19336589A JP H0355872 A JPH0355872 A JP H0355872A
- Authority
- JP
- Japan
- Prior art keywords
- film
- polycrystalline silicon
- silicon film
- oxide film
- type
- 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.)
- Pending
Links
- 229910021420 polycrystalline silicon Inorganic materials 0.000 title claims abstract description 48
- 238000000034 method Methods 0.000 title claims description 8
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title abstract description 5
- 229910052710 silicon Inorganic materials 0.000 title abstract description 5
- 239000010703 silicon Substances 0.000 title abstract description 5
- 230000015572 biosynthetic process Effects 0.000 claims description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 abstract description 18
- 230000003647 oxidation Effects 0.000 abstract description 6
- 238000007254 oxidation reaction Methods 0.000 abstract description 6
- 239000012535 impurity Substances 0.000 abstract description 5
- 229910052814 silicon oxide Inorganic materials 0.000 abstract description 5
- 239000000758 substrate Substances 0.000 abstract description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 2
- 239000012299 nitrogen atmosphere Substances 0.000 abstract description 2
- 229910052760 oxygen Inorganic materials 0.000 abstract description 2
- 239000001301 oxygen Substances 0.000 abstract description 2
- 230000001590 oxidative effect Effects 0.000 abstract 1
- 229920005591 polysilicon Polymers 0.000 abstract 1
- 238000009792 diffusion process Methods 0.000 description 4
- 230000015654 memory Effects 0.000 description 4
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 3
- 229910052698 phosphorus Inorganic materials 0.000 description 3
- 239000011574 phosphorus Substances 0.000 description 3
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 2
- 229910052796 boron Inorganic materials 0.000 description 2
- ILAHWRKJUDSMFH-UHFFFAOYSA-N boron tribromide Chemical compound BrB(Br)Br ILAHWRKJUDSMFH-UHFFFAOYSA-N 0.000 description 2
- 229910021421 monocrystalline silicon Inorganic materials 0.000 description 2
- 229910015845 BBr3 Inorganic materials 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005468 ion implantation Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
Landscapes
- Internal Circuitry In Semiconductor Integrated Circuit Devices (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、多結晶シリコン膜上に絶縁膜を形成する方法
に於いて、特に絶縁膜の膜厚均一性の優れた形成方法に
関する.
〔発明の概要〕
本発明は、多結晶シリコン膜上に絶縁膜を形成する工程
に於いて、多結晶シリコン膜を形或後、BBr3を不純
物拡散して、前記多結晶シリコン膜をP十型にした後に
前記多結晶シリコン膜上に絶縁膜を形成することにより
膜厚均一性の優れた絶縁膜を提供するものである.
〔従来の技術〕
第2図(al〜(Clは一般的な多結晶シリコン膜上の
酸化膜の形成工程順を示す断面図である6インチP型シ
リコン基板11を用い、シリコン酸化膜12を形成し、
多結晶シリコン膜13を形成する(第2図tal参照)
.この後、リン拡敗14により多結晶シリコン膜13を
N十型化する(第2図山)参照〉。次に多結晶シリコン
酸化膜15を形或する(第2図(Cl参照).
〔発明が解決しようとする課題〕
リン拡散法によりN十型化された多結晶シリコン膜の表
面に形成される熱酸化膜には以下の欠点があった.
N十型の多結晶シリコン膜の酸化速度は単結晶シリコン
と比較して非常に大きい.従って酸化炉の出し入れの際
にウエハ内に不均一に形成される外気熱酸化膜、及びウ
エハ内の多結晶シリコン層のリン濃度のばらつきにより
、ウエノ\内で不均一な酸化膜厚となる。従来の多結晶
シリコン酸化膜の形或方法によるウエハ面内の酸化膜厚
均一性を第3図中に破線で示す。第3図は縦軸に6イン
チウエハ面内の酸化膜厚均一性、横軸に多結晶シリコン
酸化膜形成回数をとったものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of forming an insulating film on a polycrystalline silicon film, and particularly to a method of forming an insulating film with excellent film thickness uniformity. [Summary of the Invention] In the process of forming an insulating film on a polycrystalline silicon film, the present invention forms a polycrystalline silicon film and then diffuses BBr3 as an impurity to transform the polycrystalline silicon film into a P-type. By forming an insulating film on the polycrystalline silicon film after forming the polycrystalline silicon film, an insulating film with excellent film thickness uniformity is provided. [Prior Art] FIG. 2 (al to (Cl) is a cross-sectional view showing the order of steps for forming an oxide film on a general polycrystalline silicon film. Using a 6-inch P-type silicon substrate 11, a silicon oxide film 12 is formed. form,
Form a polycrystalline silicon film 13 (see tal in FIG. 2)
.. Thereafter, the polycrystalline silicon film 13 is made into an N0 type by phosphorus expansion 14 (see the top of FIG. 2). Next, a polycrystalline silicon oxide film 15 is formed (see Figure 2 (Cl)). Thermal oxide films had the following drawbacks: The oxidation rate of N0-type polycrystalline silicon films is much higher than that of single-crystal silicon.Therefore, it is formed non-uniformly within the wafer when it is taken in and out of the oxidation furnace. Due to variations in the phosphorus concentration of the external thermal oxide film and the polycrystalline silicon layer within the wafer, the oxide film thickness becomes non-uniform within the wafer. The oxide film thickness uniformity is shown by the broken line in Figure 3. In Figure 3, the vertical axis shows the oxide film thickness uniformity within the 6-inch wafer surface, and the horizontal axis shows the number of times polycrystalline silicon oxide film is formed. be.
ただしウエハ面内の酸化膜厚均一性は、ウエハ周辺部1
cmを除いた上.中,下,左,右の5ポイントの測定結
果である。However, the uniformity of the oxide film thickness within the wafer surface is
Excluding cm. These are the measurement results for 5 points: middle, bottom, left, and right.
上記の問題点を解決するために多結晶シリコン膜を形成
した直後、リン拡散によりN十型化するのではなく、多
結晶シリコン膜を形成した後に、ボロン拡散法によりP
十型化してから多結晶シリコン酸化膜を形成する。In order to solve the above problems, instead of forming a polycrystalline silicon film and converting it into an N-type by phosphorus diffusion immediately after forming the polycrystalline silicon film, a boron diffusion method is used to form a polycrystalline silicon film.
After forming a ten-shaped structure, a polycrystalline silicon oxide film is formed.
上記のような形成工程順によって形戊された多結晶シリ
コン酸化膜は、ウエハ内で均一に酸化膜厚が形成される
.
多結晶シリコン膜からなる浮遊ゲートを有する不揮発性
メモリに於いて、浮遊ゲー・ト上の酸化膜厚が安定する
ので浮遊ゲート、制御ゲート間の容量も安定し、信頼性
の高い不揮発性メモリを提供できる.
〔実施例〕
以下本発明を実施例を用いて詳細に説明する.第1図[
al〜telは本発明の多結晶シリコン酸化膜の形或工
程順を示す断面図である。6インチP型シリコン基板1
を用い、シリコン酸化膜2を形成し、多結晶シリコン膜
3を4000人形成する(第1図ta+参照)。この後
、BBr.による不純物拡散4をして多結晶シリコン膜
3をP十型にする(第1図山)参照〉.次に温度100
0℃の酸素/窒素雰囲気中で多結晶シリコン熱酸化膜5
を形或する(第1図(Cl参照).
本発明の多結晶シリコン酸化膜の形成方法によるウエハ
面内の酸化膜厚均一性を第3図中に実線で示す。第3図
から明らかなように本発明の多結晶シリコン酸化膜の膜
厚均一性は従来の多結晶シリコン酸化膜の膜厚均一性に
比べ大分良くなっているのがわかる。これはN+の多結
晶シリコン上に形成される熱酸化膜は威長レートが非常
に速いのに対して、P十の多結晶シリコン上では単結晶
シリコン上と比較しても、ほとんど変わりがない.従っ
て酸化炉の出し入れの際にウエハ内に不均一に形成され
る外気熱酸化膜やウエハ内の多結晶シリコン層の不純物
濃度のばらつきなどによる酸化膜厚の不均一性を最小限
にすることが出来る.尚、多結晶シリコン膜形成後BB
r3などによる不純物拡散によらずに、BF3などによ
るイオンインプランテーションによって多結晶シリコン
膜をP十型にすることも可能である。The polycrystalline silicon oxide film formed by the above formation process order has a uniform oxide film thickness within the wafer. In non-volatile memory that has a floating gate made of polycrystalline silicon, the thickness of the oxide film on the floating gate is stable, so the capacitance between the floating gate and control gate is also stable, making highly reliable non-volatile memory possible. Can be provided. [Examples] The present invention will be explained in detail below using examples. Figure 1 [
al to tel are cross-sectional views showing the shape and process order of the polycrystalline silicon oxide film of the present invention. 6 inch P type silicon substrate 1
A silicon oxide film 2 is formed using a silicon oxide film 2, and a polycrystalline silicon film 3 is formed by 4000 layers (see ta+ in FIG. 1). After this, BBr. The polycrystalline silicon film 3 is made into a P-type by impurity diffusion 4 (see Fig. 1). Then temperature 100
Polycrystalline silicon thermal oxide film 5 in oxygen/nitrogen atmosphere at 0°C
(see Fig. 1 (see Cl)). The uniformity of the oxide film thickness within the wafer surface by the method of forming a polycrystalline silicon oxide film of the present invention is shown by the solid line in Fig. 3. As can be seen, the film thickness uniformity of the polycrystalline silicon oxide film of the present invention is much better than that of the conventional polycrystalline silicon oxide film. The growth rate of thermal oxide films is very fast, but on P0 polycrystalline silicon there is almost no difference compared to single crystal silicon. It is possible to minimize the non-uniformity of the oxide film thickness due to the outside air thermal oxide film that is formed non-uniformly on the wafer and the variation in the impurity concentration of the polycrystalline silicon layer within the wafer. BB
It is also possible to make the polycrystalline silicon film into a P-type by ion implantation using BF3 or the like instead of using impurity diffusion using r3 or the like.
本発明は以上説明したように、ウェハサイズが6〜8イ
ンチと大きくなってもウェハ内で均一に酸化膜厚が形成
されることにより、多結晶シリコン膜からなる浮遊ゲー
トを有する不揮発性メモリに於いて、浮遊ゲート上の酸
化膜厚が安定するので、浮遊ゲート,制御ゲート間の容
量が安定し、信頼性の高い不揮発性メモリを量産するこ
とが出来る.As explained above, the present invention enables a nonvolatile memory having a floating gate made of a polycrystalline silicon film to be produced by uniformly forming an oxide film thickness within the wafer even when the wafer size increases from 6 to 8 inches. Since the thickness of the oxide film on the floating gate is stabilized, the capacitance between the floating gate and the control gate is stabilized, making it possible to mass-produce highly reliable nonvolatile memories.
第1図+al〜(Clは本発明の多結晶シリコン酸化膜
の形成工程順を示す断面図、第2図fal〜(Clは従
来の多結晶シリコン酸化膜の形成工程順を示す断面図、
第3図は従来の多結晶シリコン酸化膜と本発明の多結晶
シリコン酸化膜の膜厚均一特性図である.
P型シリコン基板
シリコン酸化膜
多結晶シリコン膜
ボロン拡敗
多結晶シリコン酸化膜
以上Figure 1+al~ (Cl is a cross-sectional view showing the order of forming steps for a polycrystalline silicon oxide film of the present invention, Figure 2 fal~ (Cl is a cross-sectional view showing the order of forming steps for a conventional polycrystalline silicon oxide film,
FIG. 3 is a film thickness uniformity characteristic diagram of a conventional polycrystalline silicon oxide film and a polycrystalline silicon oxide film of the present invention. P-type silicon substrate Silicon oxide film Polycrystalline silicon film Boron expanded polycrystalline silicon oxide film or higher
Claims (1)
コン膜をP+型で形成する工程と、前記多結晶シリコン
膜上に熱酸化膜を形成する工程とからなる多結晶シリコ
ン膜上絶縁膜の形成方法。Formation of an insulating film on a polycrystalline silicon film, which includes a step of forming a polycrystalline silicon film, a step of forming the polycrystalline silicon film as P+ type, and a step of forming a thermal oxide film on the polycrystalline silicon film. Method.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP19336589A JPH0355872A (en) | 1989-07-24 | 1989-07-24 | Forming method of silicon film on polycrystalline silicon film |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP19336589A JPH0355872A (en) | 1989-07-24 | 1989-07-24 | Forming method of silicon film on polycrystalline silicon film |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH0355872A true JPH0355872A (en) | 1991-03-11 |
Family
ID=16306703
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP19336589A Pending JPH0355872A (en) | 1989-07-24 | 1989-07-24 | Forming method of silicon film on polycrystalline silicon film |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0355872A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2020041251A (en) * | 2018-09-07 | 2020-03-19 | ロイ エス.アール.エル.Roj S.R.L. | Weft thread reflection optical sensor in weft feeder for weaving |
-
1989
- 1989-07-24 JP JP19336589A patent/JPH0355872A/en active Pending
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2020041251A (en) * | 2018-09-07 | 2020-03-19 | ロイ エス.アール.エル.Roj S.R.L. | Weft thread reflection optical sensor in weft feeder for weaving |
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