Koninklijke Philips Corporation N.v.

U.S. Philips Corporation

Nxp B.v.

Koninklijke Phillips Electronics N.v.

Eddie Huang

Steven Thomas Peake

Raymond J E Hueting

Godefridus A M Hurkx

Wiebe B De Boer

Hendrik G A Huizing

Adam Brown

Miron Drobnis

Martin J Hill

Sandra M Crosbie

A semiconductor device, for example a MOSFET or IGBT, includes a region () in the drain drift region () juxtaposed with its channel-accommodating region () and spaced from the drain contact region () by means of an intermediate portion of the drift region. The region comprises alternating stripes () of the first and second conductivity types, which stripes extend alongside the channel-accommodating region (). In a trench gated device the stripes are elongated in a direction perpendicular to the trench walls. In a planar gate device the stripes extend around the periphery of the channel-accommodating region () leaving the region near the gate in a direction perpendicular with respect to the gate electrotes. The dimensions and doping levels of the stripes () are selected such that region () provides a voltage-sustaining space-charge zone when depleted. The invention enables reduction of lateral current spreading resistance in the drain drift region () without significantly degrading the breakdown properties of the device.

Semiconductor devices and methods of manufacture thereof

A metal-oxide-semiconductor trench-gate semiconductor device in which a substantially intrinsic region ( ) is provided below the gate trench ( ), which extends from the base of the trench, substantially across the drain drift region ( ) towards the drain contact region ( ), such that when the drain-source voltage falls during turn-on of the device its rate of decrease is higher. This reduces the switching losses of the device. The substantially intrinsic region ( ) may, for example, be formed by implanting a region below the trench ( ) with a damage implant.

Trench-gate semiconductor devices and the manufacture thereof

A semiconductor rectifier includes an intermediate semiconductor region ( ) extending between anode ( ) and cathode ( ) contacts. A trenched gate ( ) with insulated sidewalls ( ) and base ( ) can deplete the intermediate region. However, a shield region ( ) acts to shield the intermediate region ( ) from the gate ( ) to allow current to flow in dependence on the polarity of the voltage applied between anode and cathode contacts ( ).

Semiconductor rectifier

A semiconductor diode has a low bandgap layer ( ) and an intermediate region ( ) with a plurality of field relief regions ( ) extending between the low bandgap layer ( ) and a first region ( ) of opposite conductivity type. The field relief regions deplete the intermediate region in the off state of the diode.

Rectifying diode

A bipolar p-i-n diode has a first ( ) and second ( ) region of opposite conductivity type and an intermediate drift region ( ) between the first and second regions. Trenched field relief regions ( ) are arranged to deplete the intermediate drift region ( ) when the diode is reverse biased, so permitting a higher doping ( ) to be used for the intermediate drift region ( ) for a given breakdown voltage. This improves both the turn-on and turn-off characteristics of the diode.

Bipolar diode

The invention relates to a so-called punch-through diode with a mesa ( ) comprising, in succession, a first ( ), a second ( ) and a third ( ) semiconductor region ( ) of, respectively, a first, a second and the first conductivity type, which punch-through diode is provided with two connection conductors ( ). During operation of said diode, a voltage is applied such that the second semiconductor region ( ) is fully depleted. A drawback of the known punch-through diode resides in that the current flow is too large at lower voltages. In a punch-through diode according to the invention, a part ( A, B) of the second semiconductor region ( ), which, viewed in projection, borders on the edge of the mesa ( ), is provided with a larger flux of doping atoms of the second conductivity type than the remainder ( A) of the second semiconductor region ( ). It has been found that the high current at a low voltage of the known diode is caused by the fact that the second semiconductor region ( ) at the edge of the mesa ( ) is depleted before the remainder of the second semiconductor region ( ). By locally increasing the flux of doping atoms, the depletion at the edge is delayed as compared to the remainder of the second semiconductor region. Preferably, this result is obtained by locally increasing the thickness of the second semiconductor region ( ). In this manner, a substantial current reduction at lower voltages is obtained in the diode in accordance with the invention.

Enhanced flux semiconductor device with mesa and method of manufacturing same

In a field-effect semiconductor device, for example a power MOSFET, a body portion separates a channel-accommodating region from a drain region at a surface of a semiconductor body. This body portion includes a drift region which serves for current flow of charge carriers of a first conductivity type from the conduction channel to the drain region, in a conducting mode of the device. Instead of being a single region, the body portion also includes field-relief regions of the second conductivity type, which are depleted together with the drift region in a voltage blocking mode of the device to provide a voltage-carrying space-charge region. The drain region extends at least partially around the body portion at the surface, and the relief regions are located radially in this body portion.

High voltage MOSFET with geometrical depletion layer enhancement

A trench-gate power device, for example a MOSFET, has a semiconductor body (,), for example of monocrystalline silicon, comprising a plurality of side-by-side body regions (,) which accommodate parallel conduction channels (,) adjacent the trench-gate structure (,) of the device. The channels (,) are connected in parallel between a first main electrode (,) which is common to side-by-side source regions (,) and a second region (,) which is common to the side-by-side body regions (,). The side-by-side source regions (,) comprise a layer (,) of narrow-bandgap semiconductor material (Si,Ge,) which is deposited on a major surface (,) of the body (,) to form a source p-n heterojunction (,) with the side-by-side body regions (,) of the body (,). This narrow-bandgap semiconductor material (Si,Ge,) serves to suppress second breakdown of the power device, so improving its ruggedness. Advantageously, at least some of the body regions (,) are short-circuited to the electrode (,) so as to determine their potential.

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Stockport, United Kingdom

Eddie Huang