Semiconductor device manufacturing: process – Introduction of conductivity modifying dopant into... – Diffusing a dopant
Reexamination Certificate
2000-01-24
2001-12-18
Mulpuri, Savitri (Department: 2812)
Semiconductor device manufacturing: process
Introduction of conductivity modifying dopant into...
Diffusing a dopant
C438S565000
Reexamination Certificate
active
06331477
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates generally to semiconductor devices, and more particularly, to a method for doping spherical-shaped semiconductors.
The doping process involves the controlled introduction of an impurity to a substrate, which produces subtle changes in the electrical resistivity of the substrate. Such characteristics are necessary for solid-state electronic semiconductor devices, such as a transistor or integrated circuit.
A current method to produce doped, spherical single crystal substrates involves doping the surface of a polycrystalline silicon granule, and then melting it to create a homogeneously doped crystal. Both the doping and the melting comprise two separate steps that are carried out in a furnace in sequence. A third step involves processing (i.e. partial melting/recrystallizing) the homogeneously doped crystal to produce a doped single crystal.
In U.S. Pat. Nos. 5,278,097, 5,955,776, and 5,223,452, methods and apparatuses for doping spherical-shaped semiconductors are disclosed. However, an improved method of doping the spherical shaped semiconductors, which is simpler and more economical, is desired.
SUMMARY OF THE INVENTION
The present invention, accordingly, provides a method for doping spherical semiconductors. To this end, one embodiment provides a chamber for levitating semiconductor spheres. The semiconductor spheres are then heated and melted within the chamber. A dopant is introduced into the chamber to diffuse into the molten semiconductor spheres.
In one embodiment, the method of doping a three dimensional substrate in a non-contact environment includes: receiving a three dimensional substrate; melting the three dimensional substrate to a liquid state; doping the three dimensional substrate with a dopant to create a doped three dimensional substrate; and recrystallizing the doped three dimensional substrate to create a doped three dimensional single crystal.
In one embodiment, the three dimensional substrate is a spherical shaped semiconductor.
In one embodiment, the non-contact environment can be achieved by floating or levitating the substrate, such as through aerodynamic levitation, acoustic levitation, electromagnetic levitation or a drop tube.
In one embodiment, melting the spherical shaped semiconductor to a liquid state includes placing the spherical shaped semiconductor in a chamber connected to a heat source. The heat source may be an Inductively Coupled Plasma (ICP) torch, which may also serve to maintain the non-contact environment. Other heat sources include an infrared lamp, a resistance furnace, an electromagnetic radiation heater, or a laser.
In one embodiment, doping the spherical shaped semiconductor includes diffusing the dopant through the spherical shaped semiconductor. The dopant may be a dopant plasma produced by passing a solid dopant mixed with an inert gas through an ICP torch or by lining an ICP torch with a solid dopant. The solid dopant may be boron nitride (BN), phosphorous (P), or antimony (Sb).
In one embodiment, the dopant is a dopant vapor produced by bubbling an inert gas through a dopant liquid, mixing a dopant gas with an inert gas, or passing an inert gas over a liquified solid dopant. The dopant liquid may be phosphorous oxychloride (POCl
3
) or boron tribromide (BBr
3
).
In one embodiment, the liquified solid dopant may be antimony (Sb), phosphorous (P), or gallium (Ga). The dopant gas may be phosphine (PH
3
) or diborane (B
2
H
6
).
In one embodiment, the dopant is a dopant plasma comprised of passing the dopant vapor through an ICP torch.
In one embodiment, the dopant is a dopant vapor produced from lining the chamber with a solid dopant.
In one embodiment, the solid dopant is selected from the group consisting of boron nitride (BN), phosphorous (P), or antimony (Sb).
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U.S. Application No. 09/032,965, filed Mar. 2, 1998, entitled: Plasma Immersion Ion Processor for Fabricating Semiconductor Integrated Circuits by Murzin, et al., copy of specification, abstract and figure No. one (Attorney Docket No. 22397.62).
U.S. Application No. 09/033,180, filed Mar. 2, 1998, entitled: Inductively Coupled Plasma Powder Vaporization for Fabricating Integrated Circuits by Murzin, et al., copy of specification, abstract and figure No. one (Attorney Docket No. 22397.61).
U.S. Application No. 09/351,202, filed Jul. 9, 1999, entitled: CVD Photo Resist Deposition by Ishikawa, et al., copy of specification, abstract and figure No. one (Attorney Docket No. 22397.92.02).
U.S. Application No. 09/346,249, filed Jul. 1, 1999, entitled: High Temperature Plasma-Assisted Diffusion by Zhang, et al., copy of specification, abstract and figure No. one (Attorney Docket No. 22397.74.02).
U.S. Application No. 09/113,671, filed Jul. 10, 1998, entitled: Method and Apparatus for Blanket Aluminum CVD on Spherical Integrated Circuits by Murzin, et al., copy of specification, abstract and figure No. one (Attorney Docket No. 22397.85).
Hanabe Murali
Patel Nainesh J.
Vekris Evangellos
Ball Semiconductor Inc.
Haynes and Boone LLP
Mulpuri Savitri
LandOfFree
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