EP0259759A2 — Method for low temperature, low pressure chemical…

Claim 1

Independent Claim 108 words

A method for epitaxially depositing a silicon layer onto a substrate, including the following steps: providing said substrate in a hot wall, thermally driven CVD apparatus, establishing a total base pressure less than about 1.33 . 10⁻⁸ mbar (10⁻⁸ Torr) in said apparatus, establishing a deposition temperature less than about 800°C in said apparatus, introducing a gas containing silicon into said apparatus which gas interacts heterogeneously with said substrate to deposit a layer of silicon epitaxially thereon, the total operating pressure of said gas containing silicon being several hundred µbar (several hundred mTorr) or less, and continuing said deposition until a desired thickness of epitaxial silicon is obtained.

Claim 2

Independent Claim 108 words

A method for epitaxially depositing a silicon layer onto a substrate, including the following steps: providing said substrate in a hot wall, thermally driven CVD apparatus, establishing a total base pressure less than about 1.33 . 10⁻⁸ mbar (10⁻⁸ Torr) in said apparatus, establishing a deposition temperature less than about 800°C in said apparatus, introducing a gas containing silicon into said apparatus which gas interacts heterogeneously with said substrate to deposit a layer of silicon epitaxially thereon, the total operating pressure of said gas containing silicon being several hundred µbar (several hundred mTorr) or less, and continuing said deposition until a desired thickness of epitaxial silicon is obtained.

Claim 3

Independent Claim 108 words

A method for epitaxially depositing silicon on a plurality of substrates, comprising the steps of: placing said substrates into an isothermal, hot wall CVD reactor, evacuating said reactor to a total base pressure less than about 1.33 . 10⁻⁸ mbar, heating said reactor to a temperature of less than about 800°C, introducing a silicon-containing gas into said reactor for epitaxial deposition of silicon onto said substrates, establishing a total operating pressure of said silicon-containing gas during said epitaxial deposition of several hundred µbar (several hundred or less mTorr) or less in said reactor, and reacting said gas on said substrates to epitaxially deposit single crystal Si layers thereon.

Claim 4

Independent Claim 108 words

A method for epitaxially depositing silicon on a plurality of substrates, comprising the steps of: placing said substrates into an isothermal, hot wall CVD reactor, evacuating said reactor to a total base pressure less than about 1.33 . 10⁻⁸ mbar, heating said reactor to a temperature of less than about 800°C, introducing a silicon-containing gas into said reactor for epitaxial deposition of silicon onto said substrates, establishing a total operating pressure of said silicon-containing gas during said epitaxial deposition of several hundred µbar (several hundred or less mTorr) or less in said reactor, and reacting said gas on said substrates to epitaxially deposit single crystal Si layers thereon.

Claim 5

Independent Claim 124 words

A method for epitaxial deposition of silicon layers onto a plurality of substrates, comprising the following steps: placing said plurality of substrates into a hot wall CVD reactor, evacuating said reactor to a base ultrahigh vacuum less than the partial pressures of any contaminants in said reactor, heating said reactor to a deposition temperature less than about 800°C, introducing a gas containing silicon into said reaction chamber for epitaxial deposition of silicon onto said substrates, establishing a total operating pressure of said gas containing silicon during deposition which is sufficiently low at said deposition temperature that homogeneous reactions of said silicon-containing gas in the gas phase are substantially eliminated, and continuing said deposition until a desired thickness of said epitaxial silicon layers is obtained.

Claim 6

Independent Claim 124 words

A method for epitaxial deposition of silicon layers onto a plurality of substrates, comprising the following steps: placing said plurality of substrates into a hot wall CVD reactor, evacuating said reactor to a base ultrahigh vacuum less than the partial pressures of any contaminants in said reactor, heating said reactor to a deposition temperature less than about 800°C, introducing a gas containing silicon into said reaction chamber for epitaxial deposition of silicon onto said substrates, establishing a total operating pressure of said gas containing silicon during deposition which is sufficiently low at said deposition temperature that homogeneous reactions of said silicon-containing gas in the gas phase are substantially eliminated, and continuing said deposition until a desired thickness of said epitaxial silicon layers is obtained.

Claim 7

Independent Claim 49 words

The method according to any one of claims 1 to 3, where said total operating pressure is less than about 266 µbar(200 mTorr), even more preferred less than 66.6 µbar (50 mTorr) and most preferred between 1.33 . 10⁻² mbar (10⁻² Torr) and 1.33 . 10⁻⁴ mbar (10⁻⁴ Torr).

Claim 8

Independent Claim 32 words

The method according to any one of claims 1 to 4, where said deposition temperature is between 500 and 775°C, even more preferred between 550 and 750°C and most preferred ≦ 700°C..

Claim 9

Independent Claim 18 words

The method according to any one of claims 1 to 5, where said gas containing silicon is silane.

Claim 10

Independent Claim 30 words

The method according to any one claims 1 to 6, where the partial pressures of all contaminants in said apparatus are maintained at pressures less than 1.33 . 10⁻⁸ mbar.

Claim 11

Independent Claim 18 words

The method according to any one of claims 1 to 7, where said substrate is comprised of silicon.

Claim 12

Independent Claim 48 words

The method according to any one of claims 1 to 8, where said total base pressure and said total operating pressure established in said reactor are sufficiently low that the partial pressures of water vapor and oxygen in said reactor are less than about 1.33 . 10⁻⁸ mbar.

Claim 13

Independent Claim 36 words

The method according to any one of claims 1 to 3 and 5 to 9, where said deposition temperature is between 500 and 650°C and said total operating pressure is several hundered µbar (several hundred mTorr).

Claim 14

Independent Claim 52 words

The method according to any one of claims 1 to 10, where said substrate or substrates is/are placed in a load chamber connected to said apparatus, said load chamber being evacuated to a pressure of about 1.33 . 10⁻⁷ mbar (10⁻⁷ Torr), and then transferred from said load chamber to said apparatus.

Claim 15

Independent Claim 58 words

The method according to any one of claims 1 to 11, including the further step of doping said epitaxial silicon layer in-situ to produce an n- and/or a p-type conductivity region therein - with a p-n junction being optionally formed - , preferably by introducing an appropriate dopant containing gas or appropriate dopant containing gases into said apparatus.

Method for low temperature, low pressure chemical vapor deposition of epitaxial silicon layers

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