Methods and devices related to radio frequency devices

Patent metadata

Field	Value
Publication number	US-12362191-B2
Application number	US-202418407877-A
Country	US
Kind code	B2
Filing date	Jan 9, 2024
Priority date	Aug 8, 2019
Publication date	Jul 15, 2025
Grant date	Jul 15, 2025

Abstract

A device includes a thinned semiconductor substrate having a first side and a second side opposite to the first side; and at least one radio frequency device at the first side, wherein the second side of the thinned semiconductor substrate is processed to reduce leakage currents or to improve a radio frequency linearity of the at least one radio frequency device through Bosch etching.

First claim

What is claimed is:

1. A method of forming a device, the method comprising:
providing a semiconductor substrate having a first side and a second side opposite the first side, wherein a thickness of the semiconductor substrate is 70 μm or less;
forming at least two radio frequency devices at the first side of the semiconductor substrate,
forming a processed region at the second side of the semiconductor substrate, wherein the processed region is configured to provide additional ion gettering at the second side of the semiconductor substrate and wherein the processed region comprises one or more of:
a defect rich layer,
a doped layer with a dopant concentration higher than in a region adjacent to the doped layer,
an aluminum oxide layer; or
a reactive ion etched region; and

forming an etched region from the second side of the semiconductor substrate limited to an area between the at least two radio frequency devices.

2. The method of claim 1 , further comprising forming a heat spreading layer on the second side of the semiconductor substrate.

3. The method of claim 1 , further comprising mounting a support substrate to the second side of the semiconductor substrate.

4. The method of claim 1 , wherein the processed region substantially extends over the whole second side of the semiconductor substrate.

5. The method of claim 4 , wherein the processed region extends over at least 80% of the second side.

6. The method of claim 4 , wherein the processed region extends over at least 90% of the second side.

7. The method of claim 1 , wherein the processed region is configured to reduce a density of free charge carriers at the second side of the semiconductor substrate.

8. The method of claim 1 , wherein forming the processed region occurs before forming the at least two radio frequency devices and before forming the etched region.

9. A method of forming a device, the method comprising:
providing a thinned semiconductor substrate having a first side and a second side opposite the first side;
forming at least two radio frequency devices at the first side of the thinned semiconductor substrate;
forming a processed region at the second side of the thinned semiconductor substrate, wherein the processed region comprises one or more of:
a defect rich layer,
a doped layer with a dopant concentration higher than in a region adjacent to the doped layer,

an alumium oxide layer, or
a reactive ion etched region; and
forming an etched region from the second side of the thinned semiconductor substrate limited to an area between the at least two radio frequency devices.

10. The method of claim 9 , further comprising forming a heat spreading layer on the second side of the thinned semiconductor substrate.

11. The method of claim 9 , wherein the processed region substantially extends over the whole second side of the thinned semiconductor substrate.

12. The method of claim 11 , wherein the processed region extends over at least 80% of the second side.

13. The method of claim 11 , wherein the processed region extends over at least 90% of the second side.

14. The method of claim 9 , wherein the processed region is configured to reduce a density of free charge carriers at the second side of the thinned semiconductor substrate.

15. A method of forming a device, the method comprising:
providing a thinned semiconductor substrate having a first side and a second side opposite to the first side, wherein the thinned semiconductor substrate comprises a bottom semiconductor layer on the second side, an insulating layer on the bottom semiconductor layer, and a top semiconductor layer on the insulating layer, wherein a thickness of the bottom semiconductor layer is between 5 μm and 70 μm;
forming at least one radio frequency device at the first side; and
forming a processed region at the second side of the thinned semiconductor substrate, wherein the processed region is configured to reduce leakage currents or improve a radio frequency linearity of the at least one radio frequency device.

16. The method of claim 15 , wherein providing the thinned semiconductor substrate comprises:
providing the bottom semiconductor layer; and
thinning the bottom semiconductor layer.

17. The method of claim 15 , wherein the processed region is adapted to pin a Fermi level at or near the middle of a bandgap of the thinned semiconductor substrate.

18. The method of claim 17 , wherein the Fermi level is pinned within 0.2 eV around the middle of the bandgap.

19. The method of claim 17 , wherein the Fermi level is pinned within 0.1 eV around the middle of the bandgap.

20. The method of claim 15 , further comprising forming a heat spreading layer on the second side of the thinned semiconductor substrate.

Assignees

• Infineon Tech Dresden Gmbh & Co Kg

Inventors

• Taddiken Hans
• Butschkow Christian
• Cattaneo Andrea
• Feick Henning
• Heiss Dominik
• Kadow Christoph
• Seidel Uwe
• Solomko Valentyn
• Steltenpohl Anton

Classifications

• H10P90/124 Primary

  by processing the backside of the wafers · CPC title

• H10P36/07

  of silicon-on-insulator structures · CPC title

• H10P30/208

  of electrically inactive species · CPC title

• H10P30/204

  into Group IV semiconductors · CPC title

• H10W74/43

  comprising oxides, nitrides or carbides, e.g. ceramics or glasses · CPC title