EP0147893A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Semiconductor devices
Assignee: Philips Electronics UK Ltd
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Filing: 1984-12-14
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Granted: —
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Expires: 2004-12-14
Abstract
Abstract Separate areas of an active unipolar barrier (3), e.<sup>g.</sup> a Schottky barrier, of a semiconductor device are located between closely-spaced field-relief regions (4) which provide the device with an improved voltage blocking characteristic. The flow of minority carriers into the adjacent body portion (2) under forward bias is restricted by providing, at least at the areas of the field-relief regions (4), a layer (14) of different material from that of the body portion (2) and from that of the unipolar barrier-forming means (11). The layer (14) of different material may form a high-impedance electrical connection with the field-relief regions 4, and/or it may form with the body portion a heterojunction such as, for example, a Schottky barrier of higher barrier height, a barrier between different band gap materials or a MIS structure, which heterojunction forms part of the field-relief regions (4).
Inventors
- 👤 John Martin Shannon
- 👤 John Alfred George Slatter
- 👤 David James Coe
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 09:26
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/60; H10D30/64; H10D30/66; H10D30/668; H10D62/00; H10D62/10; H10D62/102; H10D62/103; H10D62/105; H10D62/106; H10D64/00; H10D64/111; H10D64/117; H10D64/118; H10D8/00; H10D8/60; H10D8/825
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
157 words
A semiconductor device comprising a semiconductor body a portion of which is of one conductivity type, unipolar barrier-forming means which forms an active barrier with said body portion at a plurality of separate areas, and closely-spaced field-relief regions which protrude to a depth in the body below the active barrier, the separate areas of the active barrier being located between the closely-spaced field-relief regions, the field-relief regions being sufficiently closely spaced that depletion layers extending in the body portion from neighbouring field-relief regions merge together under reverse-bias of the active barrier to provide the device with an improved voltage blocking characteristic, characterised in that a layer of different material from that of the body portion and from that of the unipolar barrier-forming means is present at least at the area of the field-relief regions and provides the field-relief regions with means restricting the flow of minority carriers into the body portion under forward-bias of the active barrier.
Claim 2
Dependent Claim
157 words
A semiconductor device comprising a semiconductor body a portion of which is of one conductivity type, unipolar barrier-forming means which forms an active barrier with said body portion at a plurality of separate areas, and closely-spaced field-relief regions which protrude to a depth in the body below the active barrier, the separate areas of the active barrier being located between the closely-spaced field-relief regions, the field-relief regions being sufficiently closely spaced that depletion layers extending in the body portion from neighbouring field-relief regions merge together under reverse-bias of the active barrier to provide the device with an improved voltage blocking characteristic, characterised in that a layer of different material from that of the body portion and from that of the unipolar barrier-forming means is present at least at the area of the field-relief regions and provides the field-relief regions with means restricting the flow of minority carriers into the body portion under forward-bias of the active barrier.
Claim 3
Dependent Claim
39 words
A device as claimed in Claim 1, further characterised in that a groove is present in said surface of the body at the area of the field-relief regions, and said layer of different material is present in the groove.
Claim 4
Dependent Claim
54 words
A device as claimed in Claim 2, further characterised in that said layer of different material in the groove provides the field-relief regions and forms a heterojunction with the body portion at the walls of the grooves, said heterojunction providing the means restricting said flow of minority carriers under forward-bias of the active barrier.
Claim 5
Dependent Claim
38 words
A device as claimed in Claim 3, further characterised in that said layer of different material is a metal-based layer which forms with the body portion a Schottky barrier having a higher barrier height than the active barrier.
Claim 6
Dependent Claim
33 words
A device as claimed in Claim 3, further characterised in that said layer of different material is a semiconductor layer having a wider energy band gap than the semiconductor material of the body.
Claim 7
Dependent Claim
36 words
A device as claimed in Claim 3, further characterised in that said layer of different material is of dielectric material and is overlaid by an electrode to form the field-relief regions as a capacitive field-effect structure.
Claim 8
Dependent Claim
20 words
A device as claimed in Claim 3, further characterised in that said layer of different material is of semi-insulating material.
Claim 9
Dependent Claim
92 words
A device as claimed in Claim 1 or Claim 2, wherein said field-relief regions comprise regions of said opposite conductivity type formed in said body portion and in electrical connection with an electrode layer, and further characterised in that said layer of different material is located between the electrode layer and the field-relief regions to restrict current flow between the electrode layer and the field-relief regions and thereby to restrict the flow of minority carriers from these opposite conductivity type regions into the body portion under forward bias of the active barrier.
Claim 10
Dependent Claim
47 words
A device as claimed in Claim 8, further characterised in that said layer of different material is of semi-insulating material and forms between the electrode layer and the field-relief regions a high-impedance electrical connection which restricts the current flow between the electrode layer and the field-relief regions.
Claim 11
Dependent Claim
66 words
A device as claimed in Claim 8, further characterised in that said layer of different material is of insulating material located over a central area of each field-relief region of said opposite conductivity type to restrict the contact area with the electrode layer to a peripheral portion of each field-relief region and thereby to restrict the current flow between the electrode layer and the field-relief regions.
Claim 12
Dependent Claim
74 words
A device as claimed in Claim 10, in which said body portion is of silicon, and further characterised in that said layer of different material is of silicon dioxide formed by local oxidation so as to be at least partly sunk into the field-relief regions, and in that the peripheral portion of each field-relief region, as compared with said central area, has a lower conductivity type determining doping concentration diffused from said central area.
Claim 13
Independent Claim
80 words
A device as claimed in any one of the preceding claims, further characterised in that the unipolar barrier-forming means comprise a semiconductor barrier region which contains a nett impurity concentration of the opposite conductivity type and which is located between said body portion and a further semiconductor region of said one conductivity type, said barrier region being at least substantially fully depleted of free charge carriers by depletion layers formed at zero bias with the body portion and further region.
Claim 14
Independent Claim
40 words
A device as claimed in any one of Claims 1 to 11, wherein the unipolar barrier-forming means comprise a metal-based layer which is present at a surface of the body and which forms a Schottky barrier with said body portion.
References Cited (Backward Citations)
GB1229776A
Cited
US4149174A
Cited
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