摘要:
A structure protects CMOS logic from substrate minority carrier injection caused by the inductive switching of a power device. A single Integrated Circuit (IC) supports one or more power MOSFETs and one or more arrays of CMOS logic. A highly doped ring is formed between the drain of the power MOSFET and the CMOS logic array to provide a low resistance path to ground for the injected minority carriers. Under the CMOS logic is a highly doped buried layer to form a region of high recombination for the injected minority carriers. One or more CMOS devices are formed above the buried layer. The substrate is a resistive and the injected current is attenuated. The well in which the CMOS devices rest forms a low resistance ground plane for the injected minority carriers.
摘要:
Methods and apparatus are provided for a MOSFET (50, 99, 199) exhibiting increased source-drain breakdown voltage (BVdss). Source (S) (70) and drain (D) (76) are spaced apart by a channel (90) underlying a gate (84) and one or more carrier drift spaces (92, 92′) serially located between the channel (90) and the source (70, 70′) or drain (76, 76′). A buried region (96, 96′) of the same conductivity type as the drift space (92, 92′) and the source (70, 70′) or drain (76, 76′) is provided below the drift space (92, 92′), separated therefrom in depth by a narrow gap (94, 94′) and ohmically coupled to the source (70, 70′) or drain (76, 76′). Current flow (110) through the drift space produces a potential difference (Vt) across this gap (94, 94′). As the S-D voltage (Vo) and current (109, Io) increase, this difference (Vt) induces high field conduction between the drift space (92, 92′) and the buried region (96, 96′) and diverts part (112, It) of the S-D current (109, Io) through the buried region (96, 96′) and away from the near surface portions of the drift space (92, 92′) where breakdown generally occurs. Thus, BVdss is increased.
摘要:
A device includes a semiconductor substrate having a surface, a trench in the semiconductor substrate extending vertically from the surface, a body region laterally adjacent the trench, spaced from the surface, having a first conductivity type, and in which a channel is formed during operation, a drift region between the body region and the surface, and having a second conductivity type, a gate structure disposed in the trench alongside the body region, recessed from the surface, and configured to receive a control voltage is applied to control formation of the channel, and a gate dielectric layer disposed along a sidewall of the trench between the gate structure and the body region. The gate structure and the gate dielectric layer have a substantial vertical overlap with the drift region such that electric field magnitudes in the drift region are reduced through application of the control voltage.
摘要:
Power device termination structures and methods are disclosed herein. The structures include a trenched-gate semiconductor device. The trenched-gate semiconductor device includes a semiconducting material and an array of trenched-gate power transistors. The array defines an inner region including a plurality of inner transistors and an outer region including a plurality of outer transistors. The inner transistors include a plurality of inner trenches that has an average inner region spacing. The outer transistors include a plurality of outer trenches that has an average termination region spacing. The average termination region spacing is greater than the average inner region spacing or is selected such that a breakdown voltage of the plurality of outer transistors is greater than a breakdown voltage of the plurality of inner transistors.
摘要:
A device includes a semiconductor substrate having a surface, a trench in the semiconductor substrate extending vertically from the surface, a body region laterally adjacent the trench, spaced from the surface, having a first conductivity type, and in which a channel is formed during operation, a drift region between the body region and the surface, and having a second conductivity type, a gate structure disposed in the trench alongside the body region, recessed from the surface, and configured to receive a control voltage is applied to control formation of the channel, and a gate dielectric layer disposed along a sidewall of the trench between the gate structure and the body region. The gate structure and the gate dielectric layer have a substantial vertical overlap with the drift region such that electric field magnitudes in the drift region are reduced through application of the control voltage.
摘要:
Power device termination structures and methods are disclosed herein. The structures include a trenched-gate semiconductor device. The trenched-gate semiconductor device includes a semiconducting material and an array of trenched-gate power transistors. The array defines an inner region including a plurality of inner transistors and an outer region including a plurality of outer transistors. The inner transistors include a plurality of inner trenches that has an average inner region spacing. The outer transistors include a plurality of outer trenches that has an average termination region spacing. The average termination region spacing is greater than the average inner region spacing or is selected such that a breakdown voltage of the plurality of outer transistors is greater than a breakdown voltage of the plurality of inner transistors.
摘要:
Field effect devices and ICs with very low gate-drain capacitance Cgd are provided by forming a substantially empty void between the gate and the drain regions. For vertical FETS a cavity is etched in the semiconductor (SC) and provided with a gate dielectric liner. A poly-SC gate deposited in the cavity has a central fissure (empty pipe) extending through to the underlying SC. This fissure is used to etch the void in the SC beneath the poly-gate. The fissure is then closed by a dielectric plug formed by deposition or oxidation without significantly filling the etched void. Conventional process steps are used to provide the source and body regions around the cavity containing the gate, and to provide a drift space and drain region below the body region. The etched void between the gate and drain provides lower Cgd and Ron*Qg than can be achieved using low k dielectrics.
摘要:
Semiconductor structures and methods are provided for a semiconductor device (54-11, 54-12) employing a superjunction structure (81). The method comprises, forming (52-6) first spaced-apart regions (70-1, 70-2, 70-3, 70-4, etc.) of a first semiconductor material (70) of a first conductivity type, forming (52-9) second spaced-apart regions (74-1, 74-2, 74-3, etc.) of a second semiconductor material (74) of opposite conductivity type interleaved with the first space-apart regions (70-1, 70-2, 70-3, 70-4, etc.) with PN junctions therebetween, thereby forming a superjunction structure, wherein the second regions have higher mobility than the first regions for the same carrier type. Other regions (88) are provided in contact with the superjunction structure (81) to direct control current flow therethrough. In a preferred embodiment, the first material (70) is relaxed SiGe and the second material (74) is strained silicon.
摘要:
Embodiments of a method for fabricating a semiconductor device having a reduced gate-drain capacitance are provided. In one embodiment, the method includes the steps of etching a trench in a semiconductor substrate utilizing an etch mask, widening the trench to define overhanging regions of the etch mask extending partially over the trench, and depositing a gate electrode material into the trench and onto the overhanging regions. The gate electrode material merges between the overhanging regions prior to the filling of the trench to create an empty fissure within the trench. A portion of the semiconductor substrate is removed through the empty fissure to form a void cavity proximate the trench.
摘要:
Methods for forming semiconductor structures are provided for a semiconductor device employing a superjunction structure and overlying trench with embedded control gate. An embodiment comprises forming interleaved first and second spaced-apart regions of first and second semiconductor materials of different conductivity type and different mobilities so that the second semiconductor material has a higher mobility for the same carrier type than the first semiconductor material, and providing an overlying third semiconductor material in which a trench is formed with sidewalls having thereon a fourth semiconductor material that has a higher mobility than the third material, adapted to carry current between source regions, through the fourth semiconductor material in the trench and the second semiconductor material in the device drift space to the drain. In a further embodiment, the first and third semiconductor materials are relaxed materials and the second and fourth semiconductor materials are strained semiconductor materials.