Englisch > Deutsch Technik E-Technik/Elektronik power devices

ein Patenttext:

According to one aspect of the present invention, there is provided a power device, comprising a gate electrode, a source electrode, and a drain electrode provided within an active region of a semiconductor substrate of a first conductivity type; and a vertical diffusion region of a second conductivity type provided at a periphery of the active region, the vertical diffusion region extending continuously from a top surface of the substrate to a bottom surface of the substrate, wherein the vertical diffusion region includes an upper portion having a first depth, the upper portion comprising primarily a first impurity material of the second conductivity type, and a lower portion having a second depth that is substantially greater than the first depth, the lower portion comprising second impurity material of the second conductivity type, the second impurity material having a higher diffusion rate than the first impurity material.
Preferably the power device is an IGBT device, and the vertical diffusion region is a ***scribe diffusion region***.
Conveniently the first impurity material is boron and the second impurity material is aluminum.
[...]
According to another aspect of the present invention, there is provided a method for fabricating a power device, comprising providing a substrate of a first conductivity, the substrate having a front side and a backside; diffusing essentially only first impurity material of a second conductivity into the substrate from the front side to form an upper portion of a ***scribe diffusion region*** of second conductivity, and diffusing a second impurity material of the second conductivity into the substrate from the backside to form a lower portion of the ***scribe diffusion region***, the second impurity material having a faster diffusion rate than the first impurity material, wherein the upper portion and the lower portion of the ***scribe diffusion region*** meet within the substrate to define a continuous vertical diffusion region
[...]
According to embodiments of the present invention, a high voltage power device with high ratings for both forward and reverse biasing modes is provided. In one embodiment of the present invention implements a particular ***scribe diffusion*** (or isolation diffusion) process that leaves the front side of a substrate sufficiently free of surface damages to facilitate subsequent fabrication steps, e.g. high resolution lithography steps. For example, the ***scribe diffusion*** process uses a first impurity type, e.g. boron, on the front side of the substrate and a second impurity type, e.g. aluminium, on the backside of the substrate

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