Abstract:
A vertical-gate MOS transistor ( 100 ) is proposed. The vertical-gate MOS transistor is integrated in a semiconductor chip ( 120 ) of a first conductivity type having a main surface, and includes an insulated trench gate ( 110 ) extending into the semiconductor chip from the main surface to a gate depth ( d1 ), said trench gate including a control gate ( G ) and an insulation layer ( 180 ) for insulating the control gate from the semiconductor chip, a source region and a drain region of a second conductivity type formed in the semiconductor chip, at least one of the source region and drain region being adjacent to the insulation layer and extending into the semiconductor chip from the main surface to a region depth ( d2 ) lower than the gate depth, wherein the insulation layer includes an external portion ( 180a ), extending into the semiconductor chip from the main surface to a protection depth ( d4 ) lower than the gate depth, and a remaining internal portion ( 180b ), the external portion having an external thickness ( d5 ) and the internal portion having an internal thickness ( d6 ) lower than the external thickness.
Abstract:
An insulated-gate transistor (100) includes a semiconductor layer (120) of a first conductivity type, an insulated gate comprising a trench gate (110) extending into the semiconductor layer, a source and a drain regions of a second conductivity type formed in the semiconductor layer at respective sides of the trench gate, wherein each one of the source and drain regions includes a first doped region (130,140), having a first dopant concentration, formed in the semiconductor layer adjacent to the trench gate, said first dopant concentration being such that a breakdown voltage of the junction formed by the first doped region and the semiconductor layer is higher than a predetermined breakdown voltage, and a second doped region (150,160), having a second dopant concentration higher than the first dopant concentration, said second doped region being formed in the first doped region and being spaced apart from the trench gate, the second dopant concentration being adapted to form a non-rectifying contact for electrically contacting the first doped region.