Qorvo Us, Inc.

Yongjie Cui

Andrew Arthur Ketterson

Xing Gu

Xing Chen

Yu Cao

Soack Dae Yoon

Cathy Lee

Subrahmanyam V Pilla

A double-disc structure for self-biased circulators monolithically integrated on semiconductors is provided. A self-based circulator is attractive due to the great reduction in its size and weight compared to conventional circulators which have bulk permanent magnets. The development of miniaturized self-biased circulators enables monolithic integration of such circulators directly into monolithic integrated circuits (e.g., monolithic microwave integrated circuits (MMICs)) on a single chip and opens the door to full-duplex communication in radio frequency (RF) bands higher than Ka band, without suffering from the additional losses through connectors. This disclosure demonstrates a new double-disc structure by using two self-biased discs in a circulator device, which greatly improve its insertion loss, isolation, bandwidth, and power handling capability.

Double-disc structure for self-biased circulators monolithically integrated on semiconductors

A high electron mobility transistor is disclosed. The high electron mobility transistor has a gallium nitride layer with a plurality of two-dimensional electron gas channels, wherein the gallium nitride layer is disposed over a substrate. A gate contact has a gate bus disposed over the gallium nitride layer. The gate bus includes a plurality of gate feet extending from the gate bus into the gallium nitride layer. Each gate foot of the plurality of gate feet has a trapezoid-shaped cross-section with a longer base and a shorter base in parallel with a longitudinal axis of the gate bus. A source contact is disposed over the gallium nitride layer, and a drain contact is disposed over the gallium nitride layer, wherein the source contact and the drain contact are spaced apart from the gate contact and each other.

High electron mobility transistor

Integration of self-biased magnetic circulators with microwave devices is disclosed herein. In microwave and other high-frequency radio frequency (RF) applications, a magnetic circulator can be implemented with a smaller permanent magnet. Aspects disclosed herein include a process flow for producing a self-biased circulator in an integrated circuit chip. In this regard, a magnetic circulator junction can be fabricated on an active layer of a semiconductor wafer. A deep pocket or cavity is formed in an insulating substrate under the active layer. This cavity is then filled with a ferromagnetic material such that the circulator junction is self-biased within the integrated circuit chip, eliminating the need for an external magnet. The self-biased circulator provides high isolation between ports in a smaller integrated circuit.

Integration of self-biased magnetic circulators with microwave devices

A passive magnetic device (PMD) has a base electrode, a multi-port signal structure (MPSS), and a substrate therebetween. The MPSS has a central plate residing in a second plane and at least two port tabs spaced apart from one another and extending from the central plate. The substrate has a central portion that defines a mesh structure between the base electrode and the central plate of the multi-port signal structure. A plurality of magnetic pillars are provided within the mesh structure, wherein each of the plurality of the magnetic pillars are spaced apart from one another and surrounded by a corresponding portion of the mesh structure. The PMD may provide a magnetically self-biased device that may be used as a radio frequency (RF) circulator, an RF isolator, and the like.

Passive magnetic devices

A method for manufacturing a self-biased circulator includes cooling a nanocomposite material to a magnetization temperature below 200 K, applying an external magnetic field to the nanocomposite material to form a magnetic nanocomposite material, providing the magnetic nanocomposite material in a semiconductor substrate, and providing one or more metal layers over the magnetic nanocomposite material to form a circulator. By cooling and then magnetizing the nanocomposite material, a performance of the circulator may be significantly improved.

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Plano, TX, United States of America

Yongjie Cui