Semiconductor device manufacturing: process – Introduction of conductivity modifying dopant into... – Ion implantation of dopant into semiconductor region
Reexamination Certificate
2000-08-30
2002-07-09
Dang, Trung (Department: 2823)
Semiconductor device manufacturing: process
Introduction of conductivity modifying dopant into...
Ion implantation of dopant into semiconductor region
C438S520000, C438S585000
Reexamination Certificate
active
06417082
ABSTRACT:
BACKGROUND
The present invention relates to semiconductor structures, semiconductor devices, electronic devices, and methods of making each.
It is known to implant nitrogen ions into semiconductor structures at a high dose to form an interface between a silicon substrate and a sacrificial dielectric layer to strengthen the bonding between the substrate and the dielectric layer. See C. T. Liu, Y. Ma, et al., “Light Nitrogen Implant for Preparing Thin-Gate Oxides” 18 (March 1997) No. 3, New York, pp. 105-107. After implantation of nitrogen through the sacrificial dielectric layer, the layer is stripped away and another oxide is grown. The nitrogen retards oxidation, so the new dielectric layer (the gate dielectric layer) is generally less than 20 Å thick. Liu indicates that a high does is necessary to achieve the improved bonding. However, the higher the dose, the thinner the new dielectric layer. For certain semiconductor structures, a dielectric layer less than 20 Å thick is undesireable.
This known procedure adds a step to the manufacturing process because the gate dielectric layer is needed to replace the sacrificial dielectric layer that was stripped away. This procedure also does not maximize the strength of interface bonding between the silicon substrate and the gate dielectric layer that can be gained through the implantation of nitrogen. The less-than-optimal strength of the interface bonding may interfere with the flash memory application of the semiconductor structure.
SUMMARY
The structures, devices, and processes described herein address at least some of the above-identified shortcomings.
In one aspect of the invention, a process for making a semiconductor structure comprises implanting nitrogen through a layer comprising SiO
2
into a substrate comprising Si, wherein the layer is on the substrate, and wherein the layer is from about 30 Å to about 300 Å thick.
In another aspect of the invention, a process for making a semiconductor structure comprises implanting nitrogen through a layer comprising SiO
2
into a substrate comprising Si, wherein the layer is on the substrate, and the layer is from about 30 Å to about 300 Å thick, and wherein the implanting causes defects; washing the semiconductor structure; and removing the defects.
In still another aspect of the invention, A process for making a semiconductor device, comprises (a) making a semiconductor structure comprising implanting nitrogen through a non-sacrificial layer comprising SiO
2
into a substrate comprising Si, wherein the layer is on the substrate, and the layer is from about 30 Å to about 300 Å thick, and wherein the implanting causes defects; washing the semiconductor device with an aqueous solution comprising ammonium hydroxide; removing the defects; and (b) converting the semiconductor structure into a semiconductor device.
The present invention provides the foregoing and other features, and the advantages of the invention will become further apparent from the following detailed description of the presently preferred embodiments, read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of the invention and do not limit the scope of the invention, which is defined by the appended claims and equivalents thereof.
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Ramsbey Mark E.
Shiraiwa Hidehiko
Wu Yider
Yang Jean
Amin & Turocy LLP
Dang Trung
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