摘要:
A semiconductor power device includes a drift region of a first conductivity type, a well region extending above the drift region and having a second conductivity type opposite the first conductivity type, an active trench extending through the well region and into the drift region. The active trench, which includes sidewalls and bottom lined with dielectric material, is substantially filled with a first conductive layer and a second conductive layer. The second conductive layer forms a gate electrode and is disposed above the first conductive layer and is separated from the first conductive layer by an inter-electrode dielectric material. The device also includes source regions having the first conductivity type formed inside the well region and adjacent the active trench and a charge control trench that extends deeper into the drift region than the active trench and is substantially filled with material to allow for vertical charge control in the drift region. The charge control trench can be lined with a layer of dielectric material and substantially filled with conductive material. The active trench can include a second shield electrode made of conductive material disposed below the first shield electrode. The first conductive layer inside the active trench can form a secondary gate electrode that is configured to be electrically biased to a desired potential. The semiconductor device can also include a Schottky structure formed between the charge control trench and a second adjacent charge control trench.
摘要:
A method for forming thick oxide at the bottom of a trench formed in a semiconductor substrate includes forming a conformal oxide film by a sub-atmospheric chemical vapor deposition process that fills the trench and covers a top surface of the substrate. The method also includes etching the oxide film off the top surface of the substrate and inside the trench to leave a substantially flat layer of oxide having a target thickness at the bottom of the trench.
摘要:
A semiconductor power device includes a drift region of a first conductivity type, a well region extending above the drift region and having a second conductivity type opposite the first conductivity type, an active trench extending through the well region and into the drift region, source regions having the first conductivity type formed in the well region adjacent the active trench, and a first termination trench extending below the well region and disposed at an outer edge of an active region of the device. The sidewalls and bottom of the active trench are lined with dielectric material, and substantially filled with a first conductive layer forming an upper electrode and a second conductive layer forming a lower electrode, the upper electrode being disposed above the lower electrode and separated therefrom by inter-electrode dielectric material. The first termination trench can be lined with a layer of dielectric material that is thicker than the dielectric material lining the sidewalls of the active trench, and is substantially filled with conductive material.
摘要:
A method for forming power semiconductor devices having an inter-electrode dielectric (IPD) layer inside a trench includes providing a semiconductor substrate with a trench, lining the sidewalls and bottom of the trench with a first layer of dielectric material, filling the trench with a first layer of conductive material to form a first electrode, recessing the first layer of dielectric material and the first layer of conductive material to a first depth inside the trench, forming a layer of polysilicon material on a top surface of the dielectric material and conductive material inside the trench, oxidizing the layer of polysilicon material, and forming a second electrode inside the trench atop the oxidized layer and isolated from trench sidewalls by a second dielectric layer. The oxidation step can be enhanced by either chemically or physically altering the top portion polysilicon such as by implanting impurities.
摘要:
A method for forming power semiconductor devices having an inter-electrode dielectric (IPD) layer inside a trench includes providing a semiconductor substrate with a trench, lining the sidewalls and bottom of the trench with a first layer of dielectric material, filling the trench with a first layer of conductive material to form a first electrode, recessing the first layer of dielectric material and the first layer of conductive material to a first depth inside the trench, forming a layer of polysilicon material on a top surface of the dielectric material and conductive material inside the trench, oxidizing the layer of polysilicon material, and forming a second electrode inside the trench atop the oxidized layer and isolated from trench sidewalls by a second dielectric layer. The oxidation step can be enhanced by either chemically or physically altering the top portion polysilicon such as by implanting impurities.
摘要:
A field effect transistor is formed as follows. Trenches are formed in a semiconductor region of a first conductivity type. Each trench is partially filled with one or more materials. A dual-pass angled implant is carried out to implant dopants of a second conductivity type into the semiconductor region through an upper surface of the semiconductor region and through upper trench sidewalls not covered by the one or more material. A high temperature process is carried out to drive the implanted dopants deeper into the mesa region thereby forming body regions of the second conductivity type between adjacent trenches. Source regions of the first conductivity type are then formed in each body region.
摘要:
A field effect transistor includes a body region of a first conductivity type in a semiconductor region of a second conductivity type. A gate trench extends through the body region and terminating within the semiconductor region. A source region of the second conductivity type extends in the body region adjacent the gate trench. The source region and an interface between the body region and the semiconductor region define a channel region therebetween which extends along the gate trench sidewall. A channel enhancement region of the second conductivity type is formed adjacent the gate trench. The channel enhancement region partially extends into a lower portion of the channel region to thereby reduce a resistance of the channel region.
摘要:
A method for forming a shielded gate field effect transistor includes the following steps. Trenches extending into a silicon region are formed using a mask that includes a protective layer. A shield dielectric layer lining sidewalls and bottom of each trench is formed. A shield electrode is formed in a bottom portion of each trench. Protective spacers are formed along upper sidewalls of each trench. An inter-electrode dielectric is formed over the shield electrode. The protective spacers and the protective layer of the mask prevent formation of inter-electrode dielectric along the upper sidewalls of each trench and over mesa surfaces adjacent each trench. A gate electrode is formed in each trench over the inter-electrode dielectric.
摘要:
A method of forming a field effect transistor includes: forming a trench in a semiconductor region; forming a shield electrode in the trench; performing an angled sidewall implant of impurities of the first conductivity type to form a channel enhancement region adjacent the trench; forming a body region of a second conductivity type in the semiconductor region; and forming a source region of the first conductivity type in the body region, the source region and an interface between the body region and the semiconductor region defining a channel region therebetween, the channel region extending along the trench sidewall. The channel enhancement region partially extends into a lower portion of the channel region to thereby reduce a resistance of the channel region.
摘要:
A field effect transistor includes a body region of a first conductivity type in a semiconductor region of a second conductivity type. A gate trench extends through the body region and terminating within the semiconductor region. A source region of the second conductivity type extends in the body region adjacent the gate trench. The source region and an interface between the body region and the semiconductor region define a channel region therebetween which extends along the gate trench sidewall. A channel enhancement region of the second conductivity type is formed adjacent the gate trench. The channel enhancement region partially extends into a lower portion of the channel region to thereby reduce a resistance of the channel region.