EP0132009A2
Expired / Lapsed
EP
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Method of manufacturing a semiconductor device and semiconductor device manufactured by means of the method
Assignee: Koninklijke Philips NV
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Filing: 1984-07-11
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Granted: —
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Expires: 2004-07-11
Abstract
Abstract A method of manufacturing a semiconductor device having a narrow groove or slot. There are formed on a substrate (4) a heavily n-doped first silicon layer (1), on this layer an oxidation-preventing layer (3) of preferably silicon nitride and on this layer a weakly doped or undoped second silicon layer (2). By means of a first and single masking step, a part of layer (2) is removed. The remaining part is oxidized in part. The exposed layer(3) is removed without masking. Subsequently, the oxide on layer (2) is removed. By thermal oxidation, a thin oxide layer (6) is formed on layer (2) and an about ten times thicker oxide layer (7) is formed on the layer (1). After the exposed layer (3) has been etched away selectively, the oxide on layer (2) is etched away entirely and the oxide on layer (1) is etched away only superfically by dip-etching, after which the groove (8) is etched while removing simultaneously the remaining part of layer (2).
Inventors
- 👤 Henricus Godefridus Rafael Maas
- 👤 Johannes Arnoldus Appels
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 01:42
CPC Classifications
H; H10; H10D; H10D44/00; H10D44/01; H10D44/041; H10P; H10P50/00; H10P50/69; H10P50/691; H10P76/00; H10P76/40; H10P95/00; Y; Y10; Y10S; Y10S438/00; Y10S438/911; Y10S438/981
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
295 words
A method of manufacturing a semiconductor device, in which there is formed on a first silicon layer an oxidation-preventing layer on which a second silicon layer is formed, after which the second silicon layer is removed in part and is then oxidized in part during a first oxidation step, the part of the oxidation-preventing layer not covered by the oxidized second silicon layer and located above a first part 6f the first silicon layer is selectively removed and the oxide present on the second silicon layer is removed by etching, the first part of the first silicon layer and the remaining part of the second silicon layer are thermally oxidized during a second oxidation step, the uncovered part of the oxidation-preventing layer is removed by etching and then a groove is etched into the exposed part of the first silicon layer, which groove separates the first part of the first silicon layer from the remaining second part, characterized in that at least the said first part of the first silicon layer is strongly n-type conducting and has a higher doping concentration than at least the said remaining part of the second silicon layer, as a result of which during the second oxidation step only a thin oxide layer is formed on the second silicon layer and a thicker oxide layer is formed on the first silicon layer, in that then, after removing the uncovered part of the oxidation-preventing layer, by mask-free etching the oxide layer of the second silicon layer is entirely and that of the first silicon . layer is only partly removed, and in that during the step of etching the groove the remaining part of the second silicon layer located above the second part of the first silicon layer is also removed.
Claim 2
Independent Claim
295 words
A method of manufacturing a semiconductor device, in which there is formed on a first silicon layer an oxidation-preventing layer on which a second silicon layer is formed, after which the second silicon layer is removed in part and is then oxidized in part during a first oxidation step, the part of the oxidation-preventing layer not covered by the oxidized second silicon layer and located above a first part 6f the first silicon layer is selectively removed and the oxide present on the second silicon layer is removed by etching, the first part of the first silicon layer and the remaining part of the second silicon layer are thermally oxidized during a second oxidation step, the uncovered part of the oxidation-preventing layer is removed by etching and then a groove is etched into the exposed part of the first silicon layer, which groove separates the first part of the first silicon layer from the remaining second part, characterized in that at least the said first part of the first silicon layer is strongly n-type conducting and has a higher doping concentration than at least the said remaining part of the second silicon layer, as a result of which during the second oxidation step only a thin oxide layer is formed on the second silicon layer and a thicker oxide layer is formed on the first silicon layer, in that then, after removing the uncovered part of the oxidation-preventing layer, by mask-free etching the oxide layer of the second silicon layer is entirely and that of the first silicon . layer is only partly removed, and in that during the step of etching the groove the remaining part of the second silicon layer located above the second part of the first silicon layer is also removed.
Claim 3
Dependent Claim
63 words
A method as claimed in Claim 1, characterized in that after removal of the said uncovered part of the oxidation-preventing layer the oxide layer formed on the second silicon layer during the second oxidation step is removed in a first plasma, after which in a continuous etching process the etching the groove into the first silicon layer is continued in a second plasma.
Claim 4
Dependent Claim
31 words
A method as claimed in Claim 2, characterized in that the first plasma is a carbon tetrachloride (CC1 4 ) plasma and in that the second plasma is a chlorine plasma.
Claim 5
Independent Claim
30 words
A method as claimed in any one of the preceding Claims, characterized in that the second oxidation step is carried out in steam at a temperature between 700°C and 800°C.
Claim 6
Independent Claim
61 words
A method as claimed in any one of the preceding Claims, characterized in that the oxidation-preventing layer is provided on a practically undoped first silicon layer, after which the first part of the first silicon layer not covered by the oxidized second silicon layer is given a high n-type doping, the oxide on the second silicon layer masking against said doping.
Claim 7
Independent Claim
25 words
A method as claimed in any one of the preceding Claims, characterized in that the first silicon layer is etched away over its whole thickness.
Claim 8
Independent Claim
25 words
A method as claimed in any one of the preceding Claims, characterized in that the groove is covered with an oxide layer by thermal oxidation.
Claim 9
Independent Claim
48 words
A method as claimed in any one of the preceding Claims, characterized in that the first silicon layer is provided on a semiconductor substrate covered by an oxide layer, and by etching the grooves is subdivided into a number of insulated gate electrodes of a field effect device.
Claim 10
Dependent Claim
116 words
A method as claimed in Claim 5, characterized in that the first silicon layer is provided on a p-type base zone of a bipolar transistor formed in an n-type collector region through an oxide window, in that the edge of the first part of the first silicon layer is located inside the oxide window, in that by diffusion from this first part of the silicon layer an n-type emitter zone is formed in the base zone, in that after etching the groove is covered by a thermal oxide layer and in that then the oxidation-preventing layer is removed, after which the underlying second part of the first silicon layer is given a high 2 -type doping.
Claim 11
Independent Claim
84 words
A method as claimed in any one of the preceding Claims, characterized in that after the first oxidation step a particle bombardment masked by the oxide on the second silicon layer is carried out, as a result,of which the oxidation-preventing layer obtains a higher etching rate than the non-implanted part thereof and in that after removal of the oxide on the second silicon layer the bombarded part of the oxidation-preventing layer is etched away completely and the non-bombarded part is etched away only superfically.
Claim 12
Independent Claim
38 words
A method as claimed in any one of the preceding Claims, characterized in that the doping of the highly doped n-type part of the first silicon layer is at least 2.1 0 20 a t oms/cm 3 .
Claim 13
Dependent Claim
18 words
A semiconductor device manufactured by the use of the method claimed in any one of the preceding Claims.
References Cited (Backward Citations)
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