Device with epitaxial base
OwnerRoman J. Hamerskiinventor
Life of this patent
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Abstract
A high voltage electrical device (20), having a substrate layer (22), base layer (24) and top layer (26), provides high voltage properties in excess of 1000V. Slicing a wafer (28) from an ingot (30) created in by monocrystalline growth forms the substrate layer (22), and this high quality crystal is used as the high resistivity layer in the device (20). The base layer (24) is a highly doped, low resistivity, epitaxial layer deposited on the lower surface (32) of the substrate layer (22) at a fast rate greater than approximately 2 microns/minute. The top layer (26) is a diffusion layer diffused into an upper surface (34) of the substrate layer (22). To control stress in the wafer (28), the epitaxial base is doped with germanium.
Claims26
An electrical device for use in high voltage applications, the device comprising:
- a high resistivity substrate layer having a substrate conductive type, the substrate layer being formed of a high purity monocrystalline semiconductor material by crystalline growth method into an ingot which is sliced to at least a desired thickness of the substrate layer, and the substrate layer having first and second spaced and generally parallel surfaces;
- a low resistivity base epitaxial layer of semiconductor material including a base dopant and having an epitaxial conductive type, the base epitaxial layer being formed contiguous with the substrate layer first surface;
- and
- a low resistivity top layer having a top layer conductive type and being formed contiguous with the substrate layer second surface.
A semiconductor wafer having a plurality of electrical devices formed thereon, the wafer comprising:
- a top side;
- a bottom side;
- a high resistivity substrate layer having a substrate conductive type, the substrate layer being formed of a high purity monocrystalline semiconductor material and the substrate layer having first and second spaced and generally parallel surfaces;
- a low resistivity base layer of semiconductor material including a dopant and having a base conductive type, the base layer being formed contiguous with the substrate layer first surface and the bottom side;
- a low resistivity top layer having a top layer conductive type and being formed contiguous with the substrate layer second surface and the top side;
- a grid of intersecting channels formed in a selected one of the top side and the bottom side, the channels separating the electrical devices from each other.
A method for fabricating a plurality of high voltage electrical devices, the method comprising:
- growing a high resistivity monocrystalline ingot from a semiconductor material having a substrate conductive type;
- slicing at least one wafer having a desired thickness from the ingot, the wafer providing a substrate including first and second spaced and generally parallel surfaces;
- forming a highly doped, low resistivity, base layer contiguous with the first surface of the substrate, and the base layer having a base layer conductive type;
- forming a low resistivity top layer contiguous with the second surface of the substrate, and the top layer having a top layer conductive type;
- and
- dividing the wafer to form separate electrical devices.
An electrical device rated at, at least approximately 1000V, the diode comprising:
- a high resistivity substrate layer having a substrate conductive type, the substrate layer being formed of a high purity monocrystalline semiconductor material and the substrate layer having first and second spaced and generally parallel surfaces;
- a low resistivity base epitaxial layer including a dopant and having an epitaxial conductive type, the base epitaxial layer being formed contiguous with the substrate layer first surface;
- and
- a low resistivity top layer having a top layer conductive type and being formed contiguous with the substrate layer second surface.
Dependencies are inferred from the claim text.