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US4933203A
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Process for depositing amorphous hydrogenated silicon in a plasma chamber
Assignee: INSTITUT DE MICROTECHNIQUE UNIVERSITE DE NEUCHATEL RUE A-L BREQUET 2 CH-2000 NEUCHATEL SWITZERLAND
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Filing: 1989-07-07
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Granted: 1990-06-12
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Expires: 2009-07-07
Abstract
Abstract The installation includes a plasma chamber containing two electrodes connected to a high-frequency generator, the substrate being mounted on one of the electrodes. A gas containing at least one silicon compound is introduced into the chamber and a plasma is created by a radiofrequency between the electrodes. The invention aims to obtain a high rate of deposition of amorphous semiconducting silicon on the substrate, at the same time as a small number of defects in the deposited film. This objective is achieved by selecting, for the ratio f/d between the frequency and the distance separating the electrodes, an optimum value included between 30 and 100 MHz/cm, the frequency being included between 25 and 150 MHz. For the optimum frequency, the deposition rate is a maximum and the number of defects is a minimum. This process may be utilized for the deposition of amorphous hydrogenated silicon or an alloy thereof from different gases or gas mixtures, and also for producing doped layers.
Inventors
- 👤 Hermann Curtins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 14:29
CPC Classifications
C; C23; C23C; C23C16/00; C23C16/44; C23C16/50; C23C16/505; C23C16/509; C23C16/5096; C23C16/22
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
126 words
A process for depositing a semiconductor film of amorphous hydrogenated silicon, an alloy of amorphous hydrogenated silicon, or mixtures thereof, on a substrate in a plasma chamber containing at least one pair of electrodes connected to a high frequency electric generator, wherein the substrate is connected to one electrode and positioned at a predetermined distance between 1 and 3 cm from the other electrode, wherein a gas containing at least one silicon compound is introduced into said chamber, electrical power at a frequency between 25 and 150 MHz is applied to said electrodes to produce a plasma therebetween, and wherein a self-confinement of the plasma between said electrodes is obtained by selecting a ratio of the frequency to said predetermined distance between 30 and 100 MHz/cm.
Claim 2
Dependent Claim
126 words
A process for depositing a semiconductor film of amorphous hydrogenated silicon, an alloy of amorphous hydrogenated silicon, or mixtures thereof, on a substrate in a plasma chamber containing at least one pair of electrodes connected to a high frequency electric generator, wherein the substrate is connected to one electrode and positioned at a predetermined distance between 1 and 3 cm from the other electrode, wherein a gas containing at least one silicon compound is introduced into said chamber, electrical power at a frequency between 25 and 150 MHz is applied to said electrodes to produce a plasma therebetween, and wherein a self-confinement of the plasma between said electrodes is obtained by selecting a ratio of the frequency to said predetermined distance between 30 and 100 MHz/cm.
Claim 3
Dependent Claim
15 words
The process claimed in claim 1, wherein said ratio is between 30 and 80 MHz/cm.
Claim 4
Dependent Claim
24 words
The process claimed in claim 2, wherein said frequency is between 30 and 100 MHz and said distance is between 1 and 2.5 cm.
Claim 5
Dependent Claim
44 words
The process claimed in claim 1, wherein the ratio of electrical power dissipated in said plasma and measured at the terminals of said two electrodes to the volume of said plasma present between said two electrodes is between 0.02 and 0.2 W/cm 2 .
Claim 6
Dependent Claim
22 words
The process claimed in claim 1, wherein a pressure ranging between 0.1 and 0.5 mbar is maintained in said chamber during deposition.
Claim 7
Dependent Claim
21 words
The process claimed in claim 1, wherein said substrate is maintained during deposition at a temperature between 230° and 350° C.
Claim 8
Dependent Claim
28 words
The process claimed in claim 1, wherein said gas introduced into said chamber comprises at least one of silane, disilane, silanes of higher order, silicon tetrafluoride, and hydrogen.
Claim 9
Dependent Claim
25 words
The process claimed in claim 7, wherein said gas includes at least one of germanium tetrahydride, germanium tetrafluoride, methane, carbontetrafluoride, nitrogen, ammonia, phosphine, and boroethane.
Claim 10
Dependent Claim
37 words
The process claimed in claim 7, wherein said gas is silane and is introduced into said chamber at a flow rate between 0.3 and 2.0 sccm (cm 2 NTP/min) per liter of internal volume of said chamber.
Claim 11
Dependent Claim
47 words
The process claimed in claim 8, wherein a film of a silicon-nitrogen alloy is deposited, wherein said gas introduced into said chamber comprises a mixture of silane and ammonia in a volumetric ratio between 0.03 and 0.3, and said predetermined distance is between 1 and 3 cm.
Claim 12
Dependent Claim
24 words
The process claimed in claim 1, wherein the plasma is confined between said pair of electrodes without use of a grid surrounding said plasma.
Claim 13
Dependent Claim
27 words
The process claimed in claim 11, wherein said plasma is confined by selecting an optimum value of said frequency for a given value of said predetermined distance.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-06-11 | 1993-12-11 | 1994-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-06-11 | 1997-12-11 | 1998-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-06-11 | 2001-12-11 | 2002-06-12 | $7700.00 | Window Closed / Lapsed |