Abstract: A lateral finger field effect transistor that has a gate bus that extends through an intermediate position of the fingers, and where the source fingers also extend from a source bus positioned also at the intermediate position. This reduces the length of the gate finger terminals and the source finger terminals, and thus reduces the voltage drop along the gate and source finger terminals. Thus, when the transistor is on, the gate-to-source voltage is better preserved along the entire length of the fingers. Accordingly, the lateral finger field effect transistors is more properly biased along the full length of the fingers of the field effect transistor. Furthermore, common source inductance is at least partially cancelled since the direction of current flow in the gate and source terminals is still in the opposite direction.

Abstract: The driving of a gate terminal of a High Electron Mobility Transistor (HEMT) such that the magnitude of the signal depends on temperature. Such transistors allow power to be transferred with much less power loss than conventional transistors, by using a two-dimensional electron gas (2DEG) to transfer current with high mobility. The reduced power loss is enabled by the high mobility of charge carriers in the 2DEG. Such a transistor has a channel semiconductor layer composed of a III-Nitride semiconductor. The channel semiconductor layer is immediately beneath a barrier semiconductor layer to form a heterojunction interface with the barrier semiconductor layer, which induces the 2DEG within the channel semiconductor layer. By applying lower temperatures to the gate terminal of the transistor than at higher temperatures, damage to the transistor is avoided.

Abstract: The driving of a gate terminal of a High Electron Mobility Transistor (HEMT) such that the magnitude of the signal depends on temperature. Such transistors allow power to be transferred with much less power loss than conventional transistors, by using a two-dimensional electron gas (2DEG) to transfer current with high mobility. The reduced power loss is enabled by the high mobility of charge carriers in the 2DEG. Such a transistor has a channel semiconductor layer composed of a III-Nitride semiconductor. The channel semiconductor layer is immediately beneath a barrier semiconductor layer to form a heterojunction interface with the barrier semiconductor layer, which induces the 2DEG within the channel semiconductor layer. By applying lower temperatures to the gate terminal of the transistor than at higher temperatures, damage to the transistor is avoided.

Abstract: A GaN semiconductor power transistor structure with a slanted gate field plate, and a method of fabrication are disclosed. The gate field plate comprises a gate metal field plate and slanted gate field plate structure formed using contact metal and/or interconnect metal. The slanted structure of the gate field plate is defined by etching of a dielectric layer having a graded composition, to form a slanted opening that is filled with conductive metal. The dielectric thickness under the gate field plate and the slant angle are configured to shape appropriately the electric field in the region between the gate and drain.

Abstract: A GaN semiconductor power transistor structure with a stepped gate field plate, and a method of fabrication is disclosed. The stepped gate field plate is formed using contact metal and/or interconnect metal. The stepped structure of the gate field plate is defined by dielectric etching to form openings for the stepped gate field plate, and the dielectric thickness under the gate field plate is sized and stepped to shape appropriately the electric field in the region between the gate and drain. The resulting stepped gate field plate structure is less sensitive to limitations of stepped field plates fabricated by a lift-off metal process.

Abstract: Embedded packaging for high voltage, high temperature operation of power semiconductor devices is disclosed, wherein a semiconductor die is embedded in a dielectric body comprising a dielectric polymer composition characterized by a conductivity transition temperature Tc, a first activation energy EaLow for conduction in a temperature range below Tc, and a second activation energy EaHigh for conduction in a temperature range above Tc. A test methodology is disclosed for selecting a dielectric epoxy composition having values of Tc, EaLow, and EaHigh that provide a conduction value below a required reliability threshold, e.g. ?5×10?13 S/cm, for a specified operating voltage and temperature. For example, the power semiconductor device comprises a GaN HEMT rated for operation at ?100V wherein the package body is formed from a laminated dielectric epoxy composition for operation at >150 C, wherein Tc is ?75 C, EaLow is ?0.

Abstract: A semiconductor device structure for a power transistor structure wherein a drain terminal structure comprises field plates to control and reduce the peak intensity of the channel electric field at the drain terminal. By forming multiple field plates with the existing metallization layers, the generation of hot carriers and impact ionization near the drain can be reduced. For example, in a GaN HEMT, this effect is achieved with two field plates that have different capacitive coupling and overlap with the drain ohmic contact to achieve a reduction in the channel electric field. The use of this drain terminal structure may offer a reduction in increase of Rdson with aging that may be observed in devices after high voltage stress.

Abstract: GaN HEMT device structures and methods of fabrication are provided. A dielectric layer forms a p-dopant diffusion barrier, and low temperature selective growth of p-GaN within a gate slot in the dielectric layer reduces deleterious effects of out-diffusion of p-dopant into the 2DEG channel. A structured AlxGa1-xN barrier layer includes a first thickness having a first Al %, and a second thickness having a second Al %, greater than the first Al %. At least part of the second thickness of the AlxGa1-xN barrier layer in the gate region is removed, before selective growth of p-GaN in the gate region. The first Al % and first thickness are selected to determine the threshold voltage Vth and the second Al % and second thickness are selected to determine the Rdson and dynamic Rdson of the GaN HEMT, so that each may be separately determined to improve device performance, and provide a smaller input FOM (Figure of Merit).

Abstract: GaN HEMT device structures and methods of fabrication are provided. A masking layer forms a p-dopant diffusion barrier and selective growth of p-GaN in the gate region, using low temperature processing, reduces deleterious effects of out-diffusion of p-dopant into the 2DEG channel. A structured AlxGa1-xN barrier layer includes a first thickness having a first Al %, and a second thickness having a second Al %, greater than the first Al %. At least part of the second thickness of the AlxGa1-xN barrier layer in the gate region is removed, before selective growth of p-GaN in the gate region. The first Al % and first thickness are selected to determine the threshold voltage Vth and the second Al % and second thickness are selected to determine the Rdson and dynamic Rdson of the GaN HEMT, so that each may be separately determined to improve device performance, and provide a smaller input FOM (Figure of Merit).

Abstract: Embedded packaging for high voltage, high temperature operation of power semiconductor devices is disclosed, wherein a semiconductor die is embedded in a dielectric body comprising a dielectric polymer composition characterized by a conductivity transition temperature Tc, a first activation energy EaLow for conduction in a temperature range below Tc, and a second activation energy EaHigh for conduction in a temperature range above Tc. A test methodology is disclosed for selecting a dielectric epoxy composition having values of Tc, EaLow, and EaHigh that provide a conduction value below a required reliability threshold, e.g. ?5×10?13 S/cm, for a specified operating voltage and temperature. For example, the power semiconductor device comprises a GaN HEMT rated for operation at ?100V wherein the package body is formed from a laminated dielectric epoxy composition for operation at >150 C, wherein Tc is ?75 C, EaLow is ?0.

Abstract: Embedded packaging for high voltage, high temperature operation of power semiconductor devices is disclosed, wherein a semiconductor die is embedded in a dielectric body comprising a dielectric polymer composition characterized by a conductivity transition temperature Tc, a first activation energy EaLow for conduction in a temperature range below Tc, and a second activation energy EaHigh for conduction in a temperature range above Tc. A test methodology is disclosed for selecting a dielectric epoxy composition having values of Tc, EaLow and EaHigh that provide a conduction value below a required reliability threshold, e.g. ?5×10?13 S/cm, for a specified operating voltage and temperature. For example, the power semiconductor device comprises a GaN HEMT for operation at >100V wherein the package body is formed from a laminated dielectric epoxy composition for operation at >150 C, wherein Tc is ?75 C, EaLow is ?0.

Abstract: Embedded packaging for high voltage, high temperature operation of power semiconductor devices is disclosed, wherein a semiconductor die is embedded in a dielectric body comprising a dielectric polymer composition characterized by a conductivity transition temperature Tc, a first activation energy EaLow for conduction in a temperature range below Tc, and a second activation energy EaHigh for conduction in a temperature range above Tc. A test methodology is disclosed for selecting a dielectric epoxy composition having values of Tc, EaLow and EaHigh that provide a conduction value below a required reliability threshold, e.g. ?5×10?13 S/cm, for a specified operating voltage and temperature. For example, the power semiconductor device comprises a GaN HEMT for operation at >100V wherein the package body is formed from a laminated dielectric epoxy composition for operation at >150 C, wherein Tc is ?75 C, EaLow is ?0.

Abstract: GaN HEMT device structures and methods of fabrication are provided. A masking layer forms a p-dopant diffusion barrier and selective growth of p-GaN in the gate region, using low temperature processing, reduces deleterious effects of out-diffusion of p-dopant into the 2DEG channel. A structured AlxGa1-xN barrier layer includes a first thickness having a first Al %, and a second thickness having a second Al %, greater than the first Al %. At least part of the second thickness of the AlxGa1-xN barrier layer in the gate region is removed, before selective growth of p-GaN in the gate region. The first Al % and first thickness are selected to determine the threshold voltage Vth and the second Al % and second thickness are selected to determine the Rdson and dynamic Rdson of the GaN HEMT, so that each may be separately determined to improve device performance, and provide a smaller input FOM (Figure of Merit).

Abstract: A GaN-on-Si device structure and a method of fabrication are disclosed for improved die yield and device reliability of high current/high voltage lateral GaN transistors. A plurality of conventional GaN device structures comprising GaN epi-layers are fabricated on a silicon substrate (GaN-on-Si die). After processing of on-chip interconnect layers, a trench structure is defined around each die, through the GaN epi-layers and into the silicon substrate. A trench cladding is provided on proximal sidewalls, comprising at least one of a passivation layer and a conductive metal layer. The trench cladding extends over exposed surfaces of the GaN epi-layers, over the interface region with the substrate, and also over the exposed surfaces of the interconnect layers. This structure reduces risk of propagation of dicing damage and defects or cracks in the GaN epi-layers into active device regions. A metal trench cladding acts as a barrier for electro-migration of mobile ions.

Abstract: A GaN-on-Si device structure and a method of fabrication are disclosed for improved die yield and device reliability of high current/high voltage lateral GaN transistors. A plurality of conventional GaN device structures comprising GaN epi-layers are fabricated on a silicon substrate (GaN-on-Si die). After processing of on-chip interconnect layers, a trench structure is defined around each die, through the GaN epi-layers and into the silicon substrate. A trench cladding is provided on proximal sidewalls, comprising at least one of a passivation layer and a conductive metal layer. The trench cladding extends over exposed surfaces of the GaN epi-layers, over the interface region with the substrate, and over the exposed surfaces of the interconnect layers. This structure reduces risk of propagation of dicing damage and defects or cracks in the GaN epi-layers into active device regions. A metal trench cladding acts as a barrier for electro-migration of mobile ions.

Abstract: A GaN-on-Si device structure and a method of fabrication are disclosed for improved die yield and device reliability of high current/high voltage lateral GaN transistors. A plurality of conventional GaN device structures comprising GaN epi-layers are fabricated on a silicon substrate (GaN-on-Si die). After processing of on-chip interconnect layers, a trench structure is defined around each die, through the GaN epi-layers and into the silicon substrate. A trench cladding is provided on proximal sidewalls, comprising at least one of a passivation layer and a conductive metal layer. The trench cladding extends over exposed surfaces of the GaN epi-layers, over the interface region with the substrate, and over the exposed surfaces of the interconnect layers. This structure reduces risk of propagation of dicing damage and defects or cracks in the GaN epi-layers into active device regions. A metal trench cladding acts as a barrier for electro-migration of mobile ions.

Abstract: A GaN-on-Si device structure and a method of fabrication are disclosed for improved die yield and device reliability of high current/high voltage lateral GaN transistors. A plurality of conventional GaN device structures comprising GaN epi-layers are fabricated on a silicon substrate (GaN-on-Si die). After processing of on-chip interconnect layers, a trench structure is defined around each die, through the GaN epi-layers and into the silicon substrate. A trench cladding is provided on proximal sidewalls, comprising at least one of a passivation layer and a conductive metal layer. The trench cladding extends over exposed surfaces of the GaN epi-layers, over the interface region with the substrate, and also over the exposed surfaces of the interconnect layers. This structure reduces risk of propagation of dicing damage and defects or cracks in the GaN epi-layers into active device regions. A metal trench cladding acts as a barrier for electro-migration of mobile ions.

Abstract: Improved high quality gate dielectrics and methods of preparing such dielectrics are provided. Preferred dielectrics comprise a rare earth doped dielectric such as silicon dioxide or silicon oxynitride. In particular, cerium doped silicon dioxide shows an unexpectedly high charge-to-breakdown QBD, believed to be due to conversion of excess hot electron energy as photons, which reduces deleterious hot electron effects such as creation of traps or other damage. Rare earth doped dielectrics therefore have particular application as gate dielectrics or gate insulators for semiconductor devices such as floating gate MOSFETs, as used in as flash memories, which rely on electron injection and charge transfer and storage.

Abstract: A light emitting device structure, wherein the emitter layer structure comprises one or more device wells defined by thick field oxide regions, and a method of fabrication thereof are provided. Preferably, by defining device well regions after depositing the emitter layer structure, emitter layer structures with reduced topography may be provided, facilitating processing and improving layer to layer uniformity. The method is particularly applicable to multilayer emitter layer structures, e.g. comprising a layer stack of active layer/drift layer pairs. Preferably, active layers comprise a rare earth oxide, or rare earth doped dielectric such as silicon dioxide, silicon nitride, or silicon oxynitride, and respective drift layers comprise a suitable dielectric, preferably silicon dioxide, of an appropriate thickness to control excitation energy. Pixellated light emitting structures, or large area, high brightness emitter layer structures, e.g.

Abstract: A GaN-on-Si device structure and a method of fabrication are disclosed for improved die yield and device reliability of high current/high voltage lateral GaN transistors. A plurality of conventional GaN device structures comprising GaN epi-layers are fabricated on a silicon substrate (GaN-on-Si die). After processing of on-chip interconnect layers, a trench structure is defined around each die, through the GaN epi-layers and into the silicon substrate. A trench cladding is provided on proximal sidewalls, comprising at least one of a passivation layer and a conductive metal layer. The trench cladding extends over exposed surfaces of the GaN epi-layers, over the interface region with the substrate, and also over the exposed surfaces of the interconnect layers. This structure reduces risk of propagation of dicing damage and defects or cracks in the GaN epi-layers into active device regions. A metal trench cladding acts as a barrier for electro-migration of mobile ions.