US-12628407-B2 - Radio frequency device and radio frequency front-end apparatus

US12628407B2US 12628407 B2US12628407 B2US 12628407B2US-12628407-B2

Abstract

A radio frequency device includes a substrate, an epitaxial structure, a first electrode, a second electrode, a gate structure, a metal bulk, an auxiliary metal bulk, and a metal connection line. The first/second electrode includes a first/second electrode body and first/second electrode fingers. The gate structure includes a sub-gate having parallel portions and vertical portions alternately connected to one another in series to form a serpentine shape. The auxiliary metal bulk is arranged between corresponding adjacent two parallel portions and between a corresponding vertical portion and an end of a corresponding first electrode finger. The metal bulk is arranged between the auxiliary metal bulk and the vertical portion corresponding to the auxiliary metal bulk. The metal connection line connects the metal bulk to the second electrode body and is insulated from the sub-gate. A radio frequency front-end apparatus including the radio frequency device is also disclosed.

Inventors

Yongming Zhang
WENBI CAI
Yang Wu
Yishu Lin
Peng Wang
Shinichiro Takatani

Assignees

XIAMEN SAN'AN INTEGRATED CIRCUIT CO., LTD.

Dates

Publication Date: 20260512
Application Date: 20230815
Priority Date: 20210218

Claims (20)

1 . A radio frequency device, comprising: a substrate; an epitaxial structure including a buffer layer, a channel layer, and a barrier layer that are disposed on said substrate in such order; a first electrode formed on said epitaxial structure and including a first electrode body and a plurality of parallel, spaced-apart first electrode fingers each extending in a first direction and connected to said first electrode body; a second electrode formed on said epitaxial structure, and including a second electrode body and a plurality of parallel, spaced-apart second electrode fingers each extending in the first direction and connected to said second electrode body, said first electrode body and said second electrode body being oppositely arranged in the first direction, said first electrode fingers and said second electrode fingers being interdigitated between said first electrode body and said second electrode body to form a serpentine channel therebetween; a gate structure including a first sub-gate that is formed on said epitaxial structure, that is disposed between said first electrode and said second electrode, and that has multiple first parallel portions each extending in the first direction and multiple first vertical portions each extending in a second direction perpendicular to the first direction, said first parallel portions and said first vertical portions being alternately connected to one another in series to form a serpentine shape and extending in said serpentine channel; a first metal bulk formed on said epitaxial structure; a first auxiliary metal bulk formed on said epitaxial structure; and a first metal connection line electrically connecting said first metal bulk to said second electrode body and electrically insulated from said first sub-gate; said first auxiliary metal bulk and said first metal bulk being arranged between corresponding adjacent two of said first parallel portions of said first sub-gate and between a corresponding one of said first vertical portions that interconnects the corresponding adjacent two of said first parallel portions and an end of a corresponding one of said first electrode fingers that is surrounded by the corresponding adjacent two of said first parallel portions and the corresponding one of first vertical portions, the end of the corresponding one of said first electrode fingers being distal from said first electrode body, said first metal bulk being positioned between said first auxiliary metal bulk and the corresponding one of said first vertical portions, one of said first electrode and said second electrode serving as a drain electrode and the other as a source electrode.
2 . The radio frequency device according to claim 1 , wherein said first auxiliary metal bulk has two opposite ends respectively connected to the corresponding adjacent two of said first parallel portions of said first sub-gate.
3 . The radio frequency device according to claim 2 , wherein said first auxiliary metal bulk is formed with a gap between the opposite ends.
4 . The radio frequency device according to claim 3 , wherein said gap is in a range from 0.05 μm to 1 μm.
5 . The radio frequency device according to claim 1 , wherein said first auxiliary metal bulk has two opposite ends in the second direction, and a gap is formed between one of the opposite ends and one of the corresponding adjacent two of said first parallel portions of said first sub-gate.
6 . The radio frequency device according to claim 5 , wherein said gap is in a range from 0.05 μm to 1 μm.
7 . The radio frequency device according to claim 1 , further comprising: a second metal bulk disposed on said epitaxial structure; a second auxiliary metal bulk disposed on said epitaxial structure; a third metal bulk disposed on said epitaxial structure; and a second metal connecting line; wherein said gate structure further includes a second sub-gate that is disposed between said first electrode and said first sub-gate, that has multiple second parallel portions each extending in the first direction and multiple second vertical portions each extending in the second direction, said second parallel portions and said second vertical portions being alternately connected to one another in series to form a serpentine shape and extending in said serpentine channel, said second auxiliary metal bulk, said second metal bulk and said third metal bulk are arranged between corresponding adjacent two of said second parallel portions of said second sub-gate, and between said first auxiliary metal bulk and an end of one of said first electrode fingers that corresponds to said first auxiliary metal bulk, said second auxiliary metal bulk is disposed between the end of said one of said first electrode fingers that corresponds to said first auxiliary metal bulk and a corresponding one of said second vertical portions that interconnects the corresponding adjacent two of said second parallel portions, said second metal bulk is disposed between said first auxiliary metal bulk and one of said second vertical portions that corresponds to said second auxiliary metal bulk, said third metal bulk is disposed between said second auxiliary metal bulk and said one of said second vertical portions that corresponds to said second auxiliary metal bulk, and said second metal bulk and said third metal bulk are interconnected by said second metal connecting line and electrically insulated from said one of said second vertical portions that corresponds to said second auxiliary metal bulk.
8 . The radio frequency device according to claim 7 , wherein said second auxiliary metal bulk has two opposite ends respectively connected to the corresponding adjacent two of said second parallel portions of said second sub-gate.
9 . The radio frequency device according to claim 8 , wherein said second auxiliary metal bulk is formed with a gap between the opposite ends.
10 . The radio frequency device according to claim 9 , wherein said gap is in a range from 0.05 μm to 1 μm.
11 . The radio frequency device according to claim 9 , wherein said first auxiliary metal bulk has a first length in the second direction, said second auxiliary metal bulk has a second length in the second direction that is shorter than the first length of said first auxiliary metal bulk, and said third auxiliary metal bulk has a third length in the second direction that is shorter than the second length of said second auxiliary metal bulk.
12 . The radio frequency device according to claim 9 , wherein said first auxiliary metal bulk, said second auxiliary metal bulk, and said third auxiliary metal bulk each has a T-shaped configuration in a cross-section along the first direction.
13 . The radio frequency device according to claim 7 , wherein said second auxiliary metal bulk has two opposite ends in the second direction, and a gap is formed between one of the opposite ends and one of the corresponding adjacent two of said second parallel portions of said second sub-gate.
14 . The radio frequency device according to claim 13 , wherein said gap is in a range from 0.05 μm to 1 μm.
15 . The radio frequency device according to claim 7 , further comprising: a third auxiliary metal bulk disposed on said epitaxial structure; wherein said gate structure further includes a third sub-gate that is disposed between said first electrode and said second sub-gate, that has multiple third parallel portions each extending in the first direction and multiple third vertical portions each extending in the second direction, said third parallel portions and said third vertical portions being alternately connected to one another in series to form a serpentine shape and extending in said serpentine channel; said third auxiliary metal bulk is arranged between corresponding adjacent two of said third parallel portions, and between an end of one of said first electrode fingers that corresponds to said first auxiliary metal bulk and a corresponding one of said third vertical portion that interconnects the corresponding adjacent two of said third parallel portions.
16 . The radio frequency device according to claim 15 , further comprising: a fourth metal bulk disposed between the corresponding third vertical portion of said third sub-gate and said second auxiliary metal bulk; a fifth metal bulk disposed between said third auxiliary metal bulk and the corresponding third vertical portion of said third sub-gate; and a third metal connecting line; wherein said fourth metal bulk and said fifth metal bulk are interconnected by said third metal connecting line and electrically insulated from said one of said third vertical portion that corresponds to said third auxiliary metal bulk.
17 . The radio frequency device according to claim 15 , wherein said third auxiliary metal bulk has two opposite ends respectively connected to the corresponding adjacent two of said third parallel portions of said third sub-gate.
18 . The radio frequency device according to claim 17 , wherein said third auxiliary metal bulk is formed with a gap between the opposite ends.
19 . The radio frequency device according to claim 15 , wherein said third auxiliary metal bulk has two opposite ends in the second direction, and a gap is formed between one of the opposite ends and one of the corresponding adjacent two of said third parallel portions of said third sub-gate.
20 . A radio frequency front-end apparatus, comprising a radio frequency device as claimed in claim 1 .

Description

CROSS-REFERENCE TO RELATED APPLICATION This application is a bypass continuation-in-part application of International Application No. PCT/CN2021/105279 filed on Jul. 8, 2021, which claims priority of Chinese Patent Application No. 202110187435.1, filed on Feb. 18, 2021. The entire content of each of the international and Chinese patent applications is incorporated herein by reference. FIELD The disclosure relates to a radio frequency device and a radio frequency front-end apparatus. BACKGROUND In the field of radio frequency microwave communications, a transmitter/receiver (TX/RX) module is utilized for multi-mode multi-frequency signal transmission and reception. The TX/RX module is configured to transmit high-power radio frequency signals emitted from front-end modules (FEMs) in a TX mode, and to receive incoming low-power radio frequency signals from antennas in an RX mode. When combined with the front-end modules and the antennas, the TX/RX module may achieve signal transmission and reception. In the TX/RX module, a switch device plays a crucial role. The isolation, insertion loss, and power handling capability of the switch device directly affect the signal transmission and reception performance of the TX/RX module. If the switch device has low power handling capability, the TX/RX module may bear a higher risk of signal leakage during operation. For example, as shown in FIGS. 1 and 2, the leakage as indicated by the dotted arrows happens during signal reception and transmission. A conventional TX/RX radio frequency device may include a single-gate structure or a multi-gate structure. A layout structure of a multi-gate radio frequency device, as shown in FIG. 3, is usually employed. Compared to a single-gate radio frequency device, the multi-gate radio frequency device has a more compact structure and lower insertion loss. A schematic diagram of a circuit of the multi-gate radio frequency device is shown in FIG. 4. However, in the multi-gate radio frequency device, gate voltages in both side regions and a middle region of a gate structure are variable, that is, these gate voltages are not set at fixed values. During the transmission of high-power signals, the input power impacts the gate voltage in the middle region of the gate structure, causing it to fluctuate. Consequently, the off-state of the gate structure in the multi-gate radio frequency device becomes unstable, leading to an increase in leakage power from a channel layer of the multi-gate radio frequency device and a decrease in the power handling capacity of the multi-gate radio frequency device. In order to address the gate voltage fluctuations with the input power of the multi-gate radio frequency device when transmitting high-power signals, the existing art teaches to provide Rds resistors with large resistances that connect area(s) between two gates and the input and output ports of the device. As shown in FIG. 5, resistors Rds1, Rds2, and Rds3 within the dashed box are designed to stabilize the voltage between the gates. However, such a design requires a significant amount of layout space for these resistors Rds, which increases the cost of the multi-gate radio frequency device. SUMMARY Therefore, an object of the disclosure is to provide a radio frequency device that may alleviate at least one of the drawbacks of the prior art, improve the performance of the radio frequency device during off-bias while improving the compactness of the device, thereby saving layout space. According to the first aspect of the disclosure, a radio frequency device includes: a substrate, an epitaxial structure, a first electrode formed on the epitaxial structure, a second electrode formed on the epitaxial structure, a gate structure, a first metal bulk formed on the epitaxial structure, a first auxiliary metal bulk formed on the epitaxial structure, and a first metal connection line. The epitaxial structure includes a buffer layer, a channel layer, and a barrier layer that are disposed on the substrate in such order. The first electrode includes a first electrode body and a plurality of parallel, spaced-apart first electrode fingers each extending in a first direction and connected to the first electrode body. The second electrode includes a second electrode body and a plurality of parallel, spaced-apart second electrode fingers each extending in the first direction and connected to the second electrode body. The first electrode body and the second electrode body being oppositely arranged in the first direction, the first electrode fingers and the second electrode fingers being interdigitated between the first electrode body and the second electrode body to form a serpentine channel therebetween. The gate structure including a first sub-gate that is formed on the epitaxial structure, that is disposed between the first electrode and the second electrode, and that has multiple first parallel portions each extending in the first direction and multiple first vert