Claims
- 1. A method of forming a doped film on a substrate, said doped film having improved uniformity of thickness on said substrate and an improved homogeneity of dopant in said film, which comprises:
- a) assembling a process tube, means for supplying a film forming gas into the process tube, means for supplying doping gas into the process tube, pump means for exhausting the process tube, and means for burning any unreacted elements in a waste gas from the method;
- b) arranging a plurality of substrates in the process tube;
- c) exhausting the process tube to maintain reduced pressure;
- d) heating the plurality of substrates in the process tube to a temperature range of 500.degree.-600.degree. C.;
- e) introducing the doping and filming forming gases into the process tube, while exhausting the process tube, a flow rate ratio of said dopant gas to said film forming gas ranging between 1.625.times.10.sup.-3 to 2.125.times.10.sup.-3, and a flow amount of the film forming gas of 48 to 807 SCCM/m.sup.2 being supplied to a unit surface area of each substrate, said film forming gas being SiH.sub.4 and said doping gas comprising PH.sub.3 in an amount of 1.+-.0.1% by volume in an inert gas; and
- f) decomposing said film forming gas and said doping gas into Si components and P components by heat, and uniformly adsorbing the Si components and the P components on an entire surface of each of the substrates by hindering the P components from being deposited on a peripheral portion at each of the substrates earlier than the Si components, thereby improving uniformity of thickness of inter-films formed on the substrates, uniformity of thickness of a film formed on the substrate, uniformity of impurity concentrations of inter-films formed on the substrates, and uniformity of impurity concentration of a film formed on the substrate.
- 2. The doped film forming method according to claim 1, wherein 300-5000 SCCM of the SiH.sub.4 gas is supplied to 170 silicon wafers whose diameters are 6 inches each.
- 3. The doped film forming method according to claim 1, wherein the speed at which the polysilicon film including the dope is formed is 30 .ANG./min or more.
- 4. The doped film forming method according to claim 1, wherein the internal pressure of the process tube is set within the range of 0.4-0.6 torr, when the gases are supplied to the process tube.
- 5. The doped film forming method according to claim 1, further comprising the steps of preparing the burning means and burning unreacted gases included in the gas exhausted from the process tube by means of the burning means.
- 6. The doped film forming method according to claim 1, wherein the wafers are rotated while the gases are being supplied to the process tube.
- 7. The doped film forming method according to claim 1, wherein the gases are introduced from a lower portion of the process tube.
- 8. The doped film forming method of claim 1, wherein the dispersion of film thickness is within a range of .+-.1% upon film forming and within a range of .+-.2 to 3.5% after annealing and a P concentration of the formed film is within a range of 5 to 6.times.10.sup.20 particles/cm.sup.3.
Priority Claims (1)
Number |
Date |
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3-122707 |
Apr 1991 |
JPX |
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Parent Case Info
This application is a Continuation of application Ser. No. 07/873,170, filed on Apr. 24, 1992, now abandoned.
US Referenced Citations (6)
Foreign Referenced Citations (1)
Number |
Date |
Country |
4326512 |
Nov 1992 |
JPX |
Non-Patent Literature Citations (2)
Entry |
Sze, VLSI Technology, McGraw-Hill, 1988, pp. 233-237. |
Kuehne, In-situ doping and trench-refill with LPCVD polysilicon I. Phosphine/silane ratio as a process-controlling parameter, CA111(24):223013t, 1989. |
Continuations (1)
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Number |
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Parent |
873170 |
Apr 1992 |
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