Anvil Semiconductors Limited

Stmicroelectronics S.r.l.

Peter Ward

Florin Udrea

Giuseppe Ferla

Simona Lorenti

Tanya Trajkovic

Neophytos Lophitis

We describe a method for reducing bow in a composite wafer comprising a silicon wafer and a silicon carbide layer grown on the silicon wafer. The method includes applying nitrogen atoms during the growth process of the silicon carbide layer on the silicon wafer so as to generate a compressive stress within the composite wafer.

Wafer bow reduction

We disclose a high voltage semiconductor device comprising a semiconductor substrate of a second conductivity type; a semiconductor drift region of the second conductivity type disposed over the semiconductor substrate, the semiconductor substrate region having higher doping concentration than the drift region; a semiconductor region of a first conductivity type, opposite to the second conductivity type, formed on the surface of the device and within the semiconductor drift region, the semiconductor region having higher doping concentration than the drift region; and a lateral extension of the first conductivity type extending laterally from the semiconductor region into the drift region, the lateral extension being spaced from a surface of the device.

High voltage semiconductor device with reduced peak electric field in active and termination areas of the device

A method comprises providing a monocrystalline silicon wafer () having a principal surface () which supports a masking layer (), for example silicon dioxide or polycrystalline silicon, having windows () to expose corresponding regions of the silicon wafer, forming silicon carbide seed regions () on the exposed regions of the wafer, for example by forming carbon and converting the carbon into silicon carbide, and growing monocrystalline silicon carbide () on the silicon carbide seed regions. Thus, monocrystalline silicon carbide can be formed selectively on the silicon wafer which can help to avoid wafer bow.

Silicon carbide epitaxy

We disclose a semiconductor structure comprising a monocrystalline silicon wafer; spaced apart monocrystalline silicon carbide layers disposed directly on the silicon wafer; amorphous and/or polycrystalline silicon carbide layers disposed directly on the silicon wafer between the monocrystalline silicon carbide layers; first gallium nitride layers disposed on the monocrystalline silicon carbide layers; and second gallium nitride layers disposed on the amorphous and/or polycrystalline silicon carbide layers.

Gallium nitride on 3C&#x2014;SiC composite wafer

A bipolar power semiconductor transistor is disclosed. The transistor includes a semiconductor substrate of a first conductivity type, a first semiconductor region of the first conductivity type disposed on the semiconductor substrate; a semiconductor drift region of a second conductivity type, opposite the first conductivity type, disposed on the first semiconductor region, a body region of the first conductivity type located within the semiconductor drift region, a source region of the second conductivity type located within the body region, a gate placed above and in contact to the source region, the gate to control charge in a channel region between the semiconductor drift region and the source region and to thereby control flow of charge within the semiconductor drift region. The semiconductor substrate includes a material having silicon (Si) and the first semiconductor region includes a material having 3-step cubic silicon carbide (3C-SiC).

3C-SiC transistor

A method for forming an interface free layer of silicon on a substrate of monocrystalline silicon is provided. According to the method, a substrate of monocrystalline silicon having a surface substantially free of oxide is provided. A silicon layer in-situ doped is deposited on the surface of the substrate in an oxygen-free environment and at a temperature below 700&deg; C. so as to produce a monocrystalline portion of the silicon layer adjacent to the substrate and a polycrystalline portion of the silicon layer spaced apart from the substrate. The silicon layer is heated so as to grow the monocrystalline portion of the silicon layer through a part of the polycrystalline portion of the silicon layer. Also provided is a method for manufacturing a bipolar transistor.

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Cambridgeshire, United Kingdom

Peter Ward