Texas Instruments Corporation

Fan-Chi Hou

Pinghai Hao

Imran Khan

Xiaoju Wu

Doug Weiser

Martin B Mollat

A semiconductor wafer includes a plurality of die areas including circuit elements, and at least one test module (TM) on the wafer outside the die areas. The TMs include a test circuit including plurality of test transistors arranged in a plurality of rows and columns. The plurality of test transistors include at least three terminals (G, S, D and B). The TMs each include a plurality of pads. The pads include a first plurality of locally shared first pads each coupled to respective ones of a first of the three terminals, a second plurality of locally shared second pads each coupled to respective ones of a second of the three terminals, and at least one of the plurality of pads coupled to a third of the three terminals. The TM provides at least 2 pin transistor selection for uniquely selecting from the plurality of test transistors for testing.

Semiconductor wafer having test modules including pin matrix selectable test devices

The disclosure herein pertains to fashioning a low noise junction field effect transistor (JFET) where transistor gate materials are utilized in forming and electrically isolating active areas of a the JFET. More particularly, active regions are self aligned with patterned gate electrode material and sidewall spacers which facilitate desirably locating the active regions in a semiconductor substrate. This mitigates the need for additional materials in the substrate to isolate the active regions from one another, where such additional materials can introduce noise into the JFET. This also allows a layer of gate dielectric material to remain over the surface of the substrate, where the layer of gate dielectric material provides a substantially uniform interface at the surface of the substrate that facilitates uninhibited current flow between the active regions, and thus promotes desired device operation.

Gate self aligned low noise JFET

Junction field effect transistors (JFETs) can be fabricated with an epitaxial layer that forms a sufficiently thick channel region to enable the JFET for use in high voltage applications (e.g., having a breakdown voltage greater than about 20V). Additionally or alternatively, threshold voltage (VT) implants can be introduced at one or more of the gate, source and drain regions to improve noise performance of the JFET. Additionally, fabrication of such a JFET can be facilitated forming the entire JFET structure concurrently with a CMOS fabrication process and/or with a BiCMOS fabrication process.

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McKinney, TX, United States of America

Fan-Chi Hou