Variable capacitor

Patent metadata

Field	Value
Publication number	US-10615294-B2
Application number	US-201816007575-A
Country	US
Kind code	B2
Filing date	Jun 13, 2018
Priority date	Jun 13, 2018
Publication date	Apr 7, 2020
Grant date	Apr 7, 2020

Abstract

A variable capacitor includes a mesa on a substrate. The mesa has multiple III-V semiconductor layers and includes a first side and a second side opposite the first side. The first side has a first sloped portion and a first horizontal portion. The second side has a second sloped portion and a second horizontal portion. A control terminal is on a third side of the mesa. A first terminal is on the first side of the mesa. The first terminal is disposed on the first horizontal portion and the first sloped portion. A second terminal is also on the substrate.

First claim

What is claimed is:

1. A variable capacitor comprising:
a mesa on a semiconductor layer, which is on a substrate, the mesa having a plurality of III-V semiconductor layers and including a first side and a second side opposite the first side, the first side having a first sloped portion and a first horizontal portion, the second side having a second sloped portion and a second horizontal portion;
a control terminal on a third side of the mesa;
a first terminal on the first side of the mesa, the first terminal disposed on the first horizontal portion and the first sloped portion; and
a second terminal on the semiconductor layer.

2. The variable capacitor of claim 1 , further comprising:
a third terminal on the second side of the mesa; and
a fourth terminal on the semiconductor layer.

3. The variable capacitor of claim 2 , further comprising a control line coupled between a plurality of terminals comprising at least two of the control terminal, the first terminal, the second terminal, the third terminal, and the fourth terminal.

4. The variable capacitor of claim 1 , in which the mesa has a graded doping profile.

5. The variable capacitor of claim 4 , in which the graded doping profile is heavily P doped proximate the control terminal, uniformly P doped to graded N doped, and/or graded P doped to graded N doped.

6. The variable capacitor of claim 4 , in which the graded doping profile is heavily N doped proximate to the control terminal, and uniformly N doped to graded P doped, and/or graded N doped to graded P doped away from the control terminal.

7. The variable capacitor of claim 4 , in which the graded doping profile is evenly P doped and N doped.

8. The variable capacitor of claim 1 , in which the second terminal is on a front-side of the semiconductor layer.

9. The variable capacitor of claim 1 , in which the semiconductor layer is N+ doped above 10 18 cm −3 .

10. The variable capacitor of claim 1 , in which the first terminal comprises a Schottky or metal-on-insulator contact.

11. The variable capacitor of claim 1 , in which the control terminal and the second terminal comprise ohmic contacts.

12. The variable capacitor of claim 1 , integrated into a radio frequency (RF) front end module, the RF front end module incorporated into at least one of a music player, a video player, an entertainment unit, a navigation device, a communications device, a personal digital assistant (PDA), a fixed location data unit, a mobile phone, and a portable computer.

Assignees

• Qualcomm Inc

Inventors

• Tao Gengming
• Li Xia
• Yang Bin
• Liang Qingqing
• Carobolante Francesco

Classifications

• H01L29/20

  Electricity · mapped topic

• H01L29/66174

  Electricity · mapped topic

• H01L29/93 Primary

  Electricity · mapped topic

• H01L29/36

  Electricity · mapped topic

• H10D62/85 Primary

  being Group III-V materials, e.g. GaAs · CPC title