Semiconductor devices and methods for forming semiconductor devices

Patent metadata

Field	Value
Publication number	US-11024502-B2
Application number	US-201916419377-A
Country	US
Kind code	B2
Filing date	May 22, 2019
Priority date	May 23, 2018
Publication date	Jun 1, 2021
Grant date	Jun 1, 2021

Abstract

A method for forming a semiconductor device includes forming a mask layer with a first implantation window on a semiconductor substrate and implanting dopants with a first implantation energy into the semiconductor substrate through the first implantation window to form a first portion of a doping region of the semiconductor device. The mask layer is adapted to form a second implantation window of the mask layer. Further, dopants are implanted with a second implantation energy into the semiconductor substrate through the second implantation window. The second implantation energy differs from the first implantation energy and a lateral dimension of the first implantation window differs from a lateral dimension of the second implantation window.

First claim

What is claimed is:

1. A method for forming a semiconductor device, the method comprising:
forming a mask layer comprising a first implantation window on a semiconductor substrate;
implanting dopants with a first implantation energy into the semiconductor substrate through the first implantation window to form a first portion of a doping region of the semiconductor device;
adapting the mask layer to form a second implantation window of the mask layer; and
implanting dopants with a second implantation energy into the semiconductor substrate through the second implantation window to form a second portion of the doping region of the semiconductor device, the second implantation energy being different from the first implantation energy, and
selecting a lateral dimension of the first implantation window to be different from a lateral dimension of the second implantation window so as to compensate for a difference in lateral straggling of dopants implanted at the first implantation energy and dopants implanted at the second implantation energy thereby reducing a difference in lateral dimensions of the first and second portions that is attributable to the difference in lateral straggling.

2. The method of claim 1 , wherein the second implantation energy is lower than the first implantation energy and/or wherein the lateral dimension of the second implantation window is larger than the lateral dimension of the first implantation window.

3. The method of claim 1 , wherein the second implantation energy is higher than the first implantation energy and/or wherein the lateral dimension of the second implantation window is smaller than the lateral dimension of the first implantation window.

4. The method of claim 1 , wherein the dopants implanted with the first implantation energy and the dopants implanted with the second implantation energy are of a first conductivity type.

5. The method of claim 1 , wherein a difference between the lateral dimension of the second implantation window and the lateral dimension of the first implantation window depends on a difference between the second implantation energy and the first implantation energy.

6. The method of claim 1 , wherein a difference between the lateral dimension of the first implantation window and the lateral dimension of the second implantation window is at least 20 nm and at most 200 nm.

7. The method of claim 1 , wherein a lateral area of the second implantation window contains a lateral area of the first implantation window.

8. The method of claim 1 , wherein adapting the mask layer comprises etching the mask layer to increase the lateral dimension of the first implantation window to obtain the second implantation window.

9. The method of claim 1 , wherein adapting the mask layer comprises forming a spacer at an edge of the first implantation window to decrease the lateral dimension of the first implantation window to obtain the second implantation window.

10. The method of claim 1 , wherein a scattering layer is located within the first implantation window during implantation of the dopants through the first implantation window.

11. The method of claim 1 , further comprising:
adapting the mask layer to form a third implantation window of the mask layer; and
implanting dopants with a third implantation energy into the semiconductor substrate through the third implantation window to form a third portion of the doping region of the semiconductor device,
wherein the third implantation energy differs from the first implantation energy and the second implantation energy,
wherein a lateral dimension of the third implantation window differs from the lateral dimension of the first implantation window and the second implantation window.

12. The method of claim 1 , wherein the mask layer has a thickness of at least 1.5 μm before adapting the mask layer to obtain the second implantation window.

13. The method of claim 1 , wherein the first implantation energy differs from the second implantation energy by at least 50 keV and by at most 2.5 MeV.

14. The method of claim 1 , wherein the semiconductor substrate is a silicon carbide substrate, a gallium arsenide substrate, or a gallium nitride substrate.

15. The method of claim 1 , wherein the doping region is at least one of or a part of an anode region of a semiconductor device, a cathode region of a semiconductor device, a base region of a semiconductor device, an emitter region of a semiconductor device, a source region of a semiconductor device, a drain region of a semiconductor device, a collector region of a semiconductor device, a body region of a semiconductor device, a gate region of a semiconductor device, a current spread region of a semiconductor device, a shielding region of a semiconductor device, and an edge termination region of a semiconductor device.

16. The method of claim 1 , wherein a maximal lateral dimension of the first portion of the doping region differs from a maximal lateral dimension of the second portion of the doping region by less than 5% of the maximal lateral dimension of the second portion of the doping region.

17. The method of claim 1 , wherein the difference in lateral dimensions between the first and second implantation windows is selected such that the lateral dimensions of the first and second portions substantially match one another.

Assignees

• Infineon Technologies Ag

Inventors

• Konrath Jens Peter
• Hilsenbeck Jochen

Classifications

• H10P76/4085

  characterised by the processes involved to create the masks · CPC title

• H10P30/22 Primary

  using masks · CPC title

• H10D30/66

  Vertical DMOS [VDMOS] FETs · CPC title

• H10D8/411

  PN diodes having planar bodies · CPC title

• H10D62/8325

  Silicon carbide · CPC title