Fault tolerant design for large area nitride semiconductor devices
First Claim
1. A device structure for a nitride semiconductor transistor comprising:
- a substrate having a nitride semiconductor layer formed on a device area of the substrate, the nitride semiconductor layer defining a plurality of active regions for an array of islands of a multi-island transistor, the array of islands extending in first and second directions over the device area,each of said active regions comprising a two dimensional electron gas (2DEG) region isolated from adjacent active regions by an intervening inactive region of the device area;
each island having a source electrode, a drain electrode and a gate electrode formed on a respective active region of the island, each source electrode having a plurality of source peninsulas, each drain electrode having a plurality of drain peninsulas, the source and drain peninsulas being interleaved and spaced apart over the active region of the island to define a channel region therebetween, the gate electrode being formed on the nitride semiconductor layer over the channel region and running between the source and drain peninsulas across the island;
each source electrode having a source contact area, each drain electrode having a drain contact area and each gate electrode having a gate contact area; and
the source, drain and gate electrodes of each island of the array of islands having an arrangement wherein each island is electrically isolated from the source, drain and gate electrodes of neighbouring islands in at least one of said first and second directions, andwherein the source, drain and gate contact areas of each island provide for electrical probing and testing of individual islands for identification of defective islands and for selective isolation of a defective island from other islands of the array.
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Abstract
A fault tolerant design for large area nitride semiconductor devices is provided, which facilitates testing and isolation of defective areas. A transistor comprises an array of a plurality of islands, each island comprising an active region, source and drain electrodes, and a gate electrode. Electrodes of each island are electrically isolated from electrodes of neighboring islands in at least one direction of the array. Source, drain and gate contact pads are provided to enable electrical testing of each island. After electrical testing of islands to identify defective islands, overlying electrical connections are formed to interconnect source electrodes in parallel, drain electrodes in parallel, and to interconnect gate electrodes to form a common gate electrode of large gate width Wg. Interconnections are provided selectively to good islands, while electrically isolating defective islands. This approach makes it economically feasible to fabricate large area GaN devices, including hybrid devices.
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Citations
29 Claims
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1. A device structure for a nitride semiconductor transistor comprising:
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a substrate having a nitride semiconductor layer formed on a device area of the substrate, the nitride semiconductor layer defining a plurality of active regions for an array of islands of a multi-island transistor, the array of islands extending in first and second directions over the device area, each of said active regions comprising a two dimensional electron gas (2DEG) region isolated from adjacent active regions by an intervening inactive region of the device area; each island having a source electrode, a drain electrode and a gate electrode formed on a respective active region of the island, each source electrode having a plurality of source peninsulas, each drain electrode having a plurality of drain peninsulas, the source and drain peninsulas being interleaved and spaced apart over the active region of the island to define a channel region therebetween, the gate electrode being formed on the nitride semiconductor layer over the channel region and running between the source and drain peninsulas across the island; each source electrode having a source contact area, each drain electrode having a drain contact area and each gate electrode having a gate contact area; and the source, drain and gate electrodes of each island of the array of islands having an arrangement wherein each island is electrically isolated from the source, drain and gate electrodes of neighbouring islands in at least one of said first and second directions, and wherein the source, drain and gate contact areas of each island provide for electrical probing and testing of individual islands for identification of defective islands and for selective isolation of a defective island from other islands of the array. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 28, 29)
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26. A device structure for a nitride semiconductor diode comprising:
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a substrate having a nitride semiconductor layer formed on a device area of the substrate and defining a plurality of active regions for an array of islands of a multi-island diode, the array of islands extending in first and second directions over the device area, each of said active regions comprising a two dimensional electron gas (2DEG) region isolated from adjacent active regions by an intervening inactive region of the device area; each island having an anode electrode and a cathode electrode formed on a respective active region of the island, each anode electrode having a plurality of anode peninsulas, each cathode electrode having a plurality of cathode peninsulas, the anode and cathode being interleaved and spaced apart over the active region of the island to define a channel region therebetween; the anode and cathode electrodes of each island each having, respectively, an anode contact area and a cathode contact area; and the anode and cathode electrodes of each island of the array of islands having an arrangement wherein at least one electrode of each island is electrically isolated from electrodes of neighbouring islands in at least one of said first and second directions, and wherein the anode and cathode contact areas of each island provide for electrical probing and testing of individual islands for identification of defective islands and for selective isolation of a defective island from other islands of the array. - View Dependent Claims (27)
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Specification