Texas Instruments Corporation

Dong Seup Lee

Jungwoo Joh

Sameer P Pendharkar

Pinghai Hao

Chang Soo Suh

Nicholas Stephen Dellas

Naveen Tipirneni

Yoshikazu Kondo

Qhalid R S Fareed

Qhalid Fareed

Karen Hildegard Ralston Kirmse

Shoji Wada

Sridhar Seetharaman

Andinet Tefera Desalegn

Hiroyuki Tomomatsu

A method of fabricating a semiconductor device includes providing a GaN substrate with an epitaxial layer formed thereover, the epitaxial layer forming a heterojunction with the GaN substrate, the heterojunction supporting a 2-dimensional electron gas (2DEG) channel in the GaN substrate. A composite surface passivation layer is formed over a top surface of the epitaxial layer, wherein the composite surface passivation layer comprises a first passivation layer portion formed proximate to a first region of the GaN device and a second passivation layer portion formed proximate to a second region of the GaN device. The first and second passivation layer portions are disposed laterally adjacent to each other over the epitaxial layer, wherein the first passivation layer portion is formed in a first process and the second passivation layer portion is formed in a second process.

Gallium nitride device having a combination of surface passivation layers

An integrated circuit (IC) includes a lower group III-N layer having a first composition over a substrate, and an upper group III-N layer having a different second composition over the lower group III-N layer. A gate electrode of a High Electron Mobility Transistor (HEMT) is located over the upper group III-N layer. First and second resistor contacts make a conductive connection to the lower group III-N layer. An unbiased group III-N cover layer is located on the upper group III-N layer in a resistor area including a high Rs 2-DEG resistor, where the unbiased group III-N cover layer is positioned between the first and second contacts.

Group III-V IC with different sheet resistance 2-DEG resistors

In some examples, a transistor comprises a gallium nitride (GaN) layer; a GaN-based alloy layer having a top side and disposed on the GaN layer, wherein source, drain, and gate contact structures are supported by the GaN layer; and a first doped region positioned in a drain access region and extending from the top side into the GaN layer.

Gallium nitride transistor with a doped region

Fabrication methods and gallium nitride transistors, in which an electronic device includes a substrate, a buffer structure, a hetero-epitaxy structure over the buffer structure, and a transistor over or in the hetero-epitaxy structure. In one example, the buffer structure has an extrinsically carbon doped gallium nitride layer over a dual superlattice stack or over a multilayer composition graded aluminum gallium nitride stack, and a silicon nitride cap layer over the hetero-epitaxy structure.

Electronic device with gallium nitride transistors and method of making same

A semiconductor device includes a gallium nitride based low threshold depletion mode transistor (GaN FET) with a threshold potential between −10 volts and −0.5 volts. The GaN FET has a channel layer of III-N semiconductor material including gallium and nitrogen that supports a two-dimensional electron gas (2DEG). The GaN FET has a barrier layer of III-N semiconductor material including aluminum and nitrogen over the channel layer. The GaN FET further has a p-type gate of III-N semiconductor material including gallium and nitrogen. A bottom surface of the gate, adjacent to the barrier layer, does not extend past a top surface of the barrier layer, located opposite from the channel layer. The GaN FET is free of a dielectric layer between the gate and the barrier layer.

Normally-on gallium nitride based transistor with p-type gate

An electronic device includes an one of aluminum gallium nitride, aluminum nitride, indium aluminum nitride, or indium aluminum gallium nitride back barrier layer over a buffer structure, a gallium nitride layer over the back barrier layer, a hetero-epitaxy structure over the gallium nitride layer, first and second transistors over the hetero-epitaxy structure, and a hole injector having a doped gallium nitride structure over the hetero-epitaxy structure and a conductive structure partially over the doped gallium nitride structure to inject holes to form a hole layer proximate an interface of the back barrier layer and the buffer structure to mitigate vertical electric field back gating effects for the first transistor.

Monolithic integration of high and low-side GaN FETs with screening back gating effect

A semiconductor structure includes a first transistor including a gate structure, a drain, and a source. The gate structure of the first transistor includes a nitride-based semiconductor layer. The semiconductor structure further includes a second transistor including a gate structure, a drain, and a source. The gate structure of the second transistor also includes a nitride-based semiconductor layer. The nitride-based semiconductor layer of the first transistor's gate structure is continuous with the nitride-based semiconductor layer of the second transistor's gate structure.

Nitride-based semiconductor layer sharing between transistors

In a described example, an integrated circuit (IC) is disclosed that includes a transistor. The transistor includes a substrate, and a buffer structure overlying the substrate. The buffer structure has a first buffer layer, a second buffer layer overlying the first buffer layer, and a third buffer layer overlying the second buffer layer. The first buffer layer has a first carbon concentration, the second buffer layer has a second carbon concentration lower than the first carbon concentration, and the third buffer layer has a third carbon concentration higher than the second carbon concentration. An active structure overlies the buffer structure.

Transistor with buffer structure having carbon doped profile

A method includes applying a DC stress condition to a transistor for a predetermined stress time, measuring an impedance of the transistor after the predetermined stress time, and repeating the application of the DC stress condition and the measurement of the impedance until the measured impedance exceeds an impedance threshold or a total stress time exceeds a time threshold, where the DC stress condition includes applying a non-zero drain voltage signal to a drain terminal of the transistor, applying a gate voltage signal to a gate terminal of the transistor, and applying a non-zero source current signal to a source terminal of the transistor.

HEMT wafer probe current collapse screening

In some examples, a transistor comprises a gallium nitride (GaN) layer; a first GaN-based alloy layer having a top side and disposed on the GaN layer; a second GaN-based alloy layer disposed on the first GaN-based alloy layer, wherein the second GaN-based alloy layer covers a first portion of the top side; and a source contact structure, a drain contact structure, and a gate contact structure, wherein the source, drain, and gate contact structures are supported by the first GaN-based alloy layer.

Transistor with multiple GaN-based alloy layers

One example provides an enhancement-mode High Electron Mobility Transistor (HEMT) includes a substrate, a Group IIIA-N active layer over the substrate, a Group IIIA-N barrier layer over the active layer, and at least one isolation region through the barrier layer to provide an isolated active area having the barrier layer on the active layer. A gate stack is located between source and drain contacts to the active layer. A tunnel diode in the gate stack includes an n-GaN layer on an InGaN layer on a p-GaN layer located on the barrier layer.

Group IIIA-N HEMT with a tunnel diode in the gate stack

An enhancement-mode High Electron Mobility Transistor (HEMT) includes a substrate, a Group IIIA-N active layer on the substrate, a Group IIIA-N barrier layer on the active layer, and at least one isolation region through the barrier layer to provide an isolated active area having the barrier layer on the active layer. A p-GaN layer is on the barrier layer. A tunnel diode in the gate stack includes an n-GaN layer on an InGaN layer on the p-GaN layer. A gate electrode is over the n-GaN layer. A drain having a drain contact is on the barrier layer to provide contact to the active layer, and a source having a source contact is on the barrier layer provides contact to the active layer. The tunnel diode provides a gate contact to eliminate the need to form a gate contact directly to the p-GaN layer.

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McKinney, TX, United States of America

Dong Seup Lee