Cambridge Electronics, Inc.

Ling Xia

Bin Lu

Mohamed Azize

Tomas Apostol Palacios

A semiconductor device such as a transistor includes a source region, a drain region, a semiconductor region, at least one island region and at least one gate region. The semiconductor region is located between the source region and the drain region. The island region is located in the semiconductor region. Each of the island regions differs from the semiconductor region in one or more characteristics selected from the group including resistivity, doping type, doping concentration, strain and material composition. The gate region is located between the source region and the drain region covering at least a portion of the island regions.

Transistor structure having buried island regions

Field-plate structures are disclosed for electrical field management in semiconductor devices. A field-plate semiconductor structure includes a semiconductor substrate, a source ohmic contact, a drain ohmic contact, and a gate contact disposed over a gate region between the source ohmic contact and the drain ohmic contact, and a source field plate connected to the source ohmic contact. A field-plate dielectric is disposed over the semiconductor substrate. An encapsulating dielectric is disposed over the gate contact, wherein the encapsulating dielectric covers a top surface of the gate contact. The source field plate is disposed over the field-plate dielectric in a field plate region, from which the encapsulating dielectric is absent.

Field-plate structures for semiconductor devices

Field-plate structures are disclosed for electrical field management in semiconductor devices. A field-plate semiconductor device comprises a semiconductor substrate, a first ohmic contact and a second ohmic contact disposed over the semiconductor substrate, one or more coupling capacitors, and one or more capacitively-coupled field plates disposed over the semiconductor substrate between the first ohmic contact and the second ohmic contact. Each of the capacitively-coupled field plates is capacitively coupled to the first ohmic contact through one of the coupling capacitors, the coupling capacitor having a first terminal electrically connected to the first ohmic contact and a second terminal electrically connected to the capacitively-coupled field plate.

Capacitively-coupled field-plate structures for semiconductor devices

A hybrid transistor circuit is disclosed for use in III-Nitride (III-N) semiconductor devices, comprising a Silicon (Si)-based Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), a Group III-Nitride (III-N)-based Field-Effect Transistor (FET), and a driver unit. A source terminal of the III-N-based FET is connected to a drain terminal of the Si-based MOSFET. The driver unit has at least one input terminal, and two output terminals connected to the gate terminals of the transistors respectively. The hybrid transistor circuit is turned on through the driver unit by switching on the Silicon-based MOSFET first before switching on the III-N-based FET, and is turned off through the driver unit by switching off the III-N-based FET before switching off the Silicon-based MOSFET. Also disclosed are integrated circuit packages and semiconductor structures for forming such hybrid transistor circuits. The resulting hybrid circuit provides power-efficient and robust use of III-Nitride semiconductor devices.

Hybrid structure with separate controls

A multi-layer semiconductor structure is disclosed for use in III-Nitride semiconductor devices, including a channel layer comprising a first III-Nitride material, a barrier layer comprising a second III-Nitride material, a pair of ohmic electrodes disposed in ohmic recesses etched into the barrier layer, a gate electrode disposed in a gate recess etched into the barrier layer, and a filler element. The gate electrode is stepped to form a bottom stem and at least one bottom step within the gate recess. The filler element, comprising an insulating material, is disposed at least below the bottom step of the gate electrode within the gate recess. Also described are methods for fabricating such semiconductor structures. The performance of resulting devices is improved, while providing design flexibility to reduce production cost and circuit footprint.

III-Nitride semiconductors with recess regions and methods of manufacture

A multi-layer semiconductor structure is disclosed for use in III-Nitride semiconductor devices, including a channel layer, a band-offset layer having a wider bandgap than the channel layer, a spacer layer having a narrower bandgap than the band-offset layer, and a cap layer comprising at least two sublayers. Each sublayer is selectively etchable with respect to sublayers immediately below and above, each sublayer comprises a III-N material AlInGaN in which 0&#x2266;x&#x2266;1, 0&#x2266;y&#x2266;1, and 0&#x2266;z&#x2266;1, at least one sublayer has a non-zero Ga content, and a sublayer immediately above the spacer layer has a wider bandgap than the spacer layer. Also described are methods for fabricating such semiconductor structures, with gate and/or ohmic recesses formed by selectively removing adjacent layers or sublayers. The performance of resulting devices is improved, while providing design flexibility to reduce production cost and circuit footprint.

Semiconductor structure with a spacer layer

Semiconductor structures are disclosed for monolithically integrating multiple III-N transistors with different threshold voltages on a common substrate. A semiconductor structure includes a cap layer comprising a plurality of selectively etchable sublayers, wherein each sublayer is selectively etchable with respect to the sublayer immediately below, wherein each sublayer comprises a material AlInGaN (0&#x2266;x, y, z&#x2266;1), and wherein at least one selectively etchable sublayer has a non-zero Ga content (0&#x3c;z&#x2266;1). A gate recess is disposed in a number of adjacent sublayers of the cap layer to achieve a desired threshold voltage for a transistor. Also described are methods for fabricating such semiconductor structures, where gate recesses and/or ohmic recesses are formed by selectively removing adjacent sublayers of the cap layer. The performance of the resulting integrated circuits is improved, while providing design flexibility to reduce production cost and circuit footprint.

Semiconductor structure and etch technique for monolithic integration of III-N transistors

A semiconductor device includes a substrate, a first active layer, a second active layer, at least first and second electrodes, an E-field management layer, and at least one injection electrode. The first active layer is disposed over the substrate. The second active layer is disposed on the first active layer such that a laterally extending conductive channel arises which extends in a lateral direction. The laterally extending conductive channel is located between the first active layer and the second active layer. The first and second electrodes are electrically connected to the first active layer. The E-field management layer, which reduces the electric-field gradients arising in the first and second active layers, is disposed over the second active layer. The injection electrode is electrically connected to the E-field management layer.

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Belmont, MA, United States of America

Ling Xia