Depth Profiling of Ion-Implanted 4H–SiC Using Confocal Raman Spectroscopy
For silicon carbide (SiC) processed by ion-implantation, dedicated test structure fabrication or destructive sample processing on test wafers are usually required to obtain depth profiles of electrical characteristics such as carrier concentration. In this study, a rapid and non-destructive approach...
Main Authors: | , , , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
MDPI AG
2020-02-01
|
Series: | Crystals |
Subjects: | |
Online Access: | https://www.mdpi.com/2073-4352/10/2/131 |
id |
doaj-a2fdf6f036094b44b17a2d97ba00cd77 |
---|---|
record_format |
Article |
spelling |
doaj-a2fdf6f036094b44b17a2d97ba00cd772020-11-25T03:19:30ZengMDPI AGCrystals2073-43522020-02-0110213110.3390/cryst10020131cryst10020131Depth Profiling of Ion-Implanted 4H–SiC Using Confocal Raman SpectroscopyYing Song0Zongwei Xu1Tao Liu2Mathias Rommel3Hong Wang4Yufang Wang5Fengzhou Fang6State Key Laboratory of Precision Measuring Technology & Instruments, Centre of Micro/Nano Manufacturing Technology, Tianjin University, Tianjin 300072, ChinaState Key Laboratory of Precision Measuring Technology & Instruments, Centre of Micro/Nano Manufacturing Technology, Tianjin University, Tianjin 300072, ChinaState Key Laboratory of Precision Measuring Technology & Instruments, Centre of Micro/Nano Manufacturing Technology, Tianjin University, Tianjin 300072, ChinaFraunhofer Institute for Integrated Systems and Device Technology, Schottkystrasse 10, 91058 Erlangen, GermanyState Key Laboratory of Separation Membranes and Membrane Processes, School of Materials Science and Engineering, Tianjin Polytechnic University, Tianjin 300387, ChinaDepartment of Physics, Nankai University, Tianjin 300071, ChinaState Key Laboratory of Precision Measuring Technology & Instruments, Centre of Micro/Nano Manufacturing Technology, Tianjin University, Tianjin 300072, ChinaFor silicon carbide (SiC) processed by ion-implantation, dedicated test structure fabrication or destructive sample processing on test wafers are usually required to obtain depth profiles of electrical characteristics such as carrier concentration. In this study, a rapid and non-destructive approach for depth profiling is presented that uses confocal Raman microscopy. As an example, a 4H−SiC substrate with an epitaxial layer of several micrometers thick and top layer in nanoscale that was modified by ion-implantation was characterized. From the Raman depth profiling, longitudinal optical (LO) mode from the epitaxial layer and longitudinal optical phonon-plasmon coupled (LOPC) mode from the substrate layer can be sensitively distinguished at the interface. The position profile of the LOPC peak intensity in the depth direction was found to be effective in estimating the thickness of the epitaxial layer. For three kinds of epitaxial layer with thicknesses of 5.3 μm, 6 μm, and 7.5 μm, the average deviations of the Raman depth analysis were −1.7 μm, −1.2 μm, and −1.4 μm, respectively. Moreover, when moving the focal plane from the heavily doped sample (~10<sup>18</sup> cm<sup>−3</sup>) to the epitaxial layer (~10<sup>16</sup> cm<sup>−3</sup>), the LOPC peak showed a blue shift. The twice travel of the photon (excitation and collection) through the ion-implanted layer with doping concentrations higher than 1 × 10<sup>18</sup> cm<sup>−3</sup> led to a difference in the LOPC peak position for samples with the same epitaxial layer and substrate layer. Furthermore, the influences of the setup in terms of pinhole size and numerical aperture of objective lens on the depth profiling results were studied. Different from other research on Raman depth profiling, the 50× long working distance objective lens (50L× lens) was found more suitable than the 100× lens for the depth analysis 4H−SiC with a multi-layer structure.https://www.mdpi.com/2073-4352/10/2/131depth profilingconfocal raman spectroscopysilicon carbidelopc mode (longitudinal optical phonon-plasmon coupled mode) |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Ying Song Zongwei Xu Tao Liu Mathias Rommel Hong Wang Yufang Wang Fengzhou Fang |
spellingShingle |
Ying Song Zongwei Xu Tao Liu Mathias Rommel Hong Wang Yufang Wang Fengzhou Fang Depth Profiling of Ion-Implanted 4H–SiC Using Confocal Raman Spectroscopy Crystals depth profiling confocal raman spectroscopy silicon carbide lopc mode (longitudinal optical phonon-plasmon coupled mode) |
author_facet |
Ying Song Zongwei Xu Tao Liu Mathias Rommel Hong Wang Yufang Wang Fengzhou Fang |
author_sort |
Ying Song |
title |
Depth Profiling of Ion-Implanted 4H–SiC Using Confocal Raman Spectroscopy |
title_short |
Depth Profiling of Ion-Implanted 4H–SiC Using Confocal Raman Spectroscopy |
title_full |
Depth Profiling of Ion-Implanted 4H–SiC Using Confocal Raman Spectroscopy |
title_fullStr |
Depth Profiling of Ion-Implanted 4H–SiC Using Confocal Raman Spectroscopy |
title_full_unstemmed |
Depth Profiling of Ion-Implanted 4H–SiC Using Confocal Raman Spectroscopy |
title_sort |
depth profiling of ion-implanted 4h–sic using confocal raman spectroscopy |
publisher |
MDPI AG |
series |
Crystals |
issn |
2073-4352 |
publishDate |
2020-02-01 |
description |
For silicon carbide (SiC) processed by ion-implantation, dedicated test structure fabrication or destructive sample processing on test wafers are usually required to obtain depth profiles of electrical characteristics such as carrier concentration. In this study, a rapid and non-destructive approach for depth profiling is presented that uses confocal Raman microscopy. As an example, a 4H−SiC substrate with an epitaxial layer of several micrometers thick and top layer in nanoscale that was modified by ion-implantation was characterized. From the Raman depth profiling, longitudinal optical (LO) mode from the epitaxial layer and longitudinal optical phonon-plasmon coupled (LOPC) mode from the substrate layer can be sensitively distinguished at the interface. The position profile of the LOPC peak intensity in the depth direction was found to be effective in estimating the thickness of the epitaxial layer. For three kinds of epitaxial layer with thicknesses of 5.3 μm, 6 μm, and 7.5 μm, the average deviations of the Raman depth analysis were −1.7 μm, −1.2 μm, and −1.4 μm, respectively. Moreover, when moving the focal plane from the heavily doped sample (~10<sup>18</sup> cm<sup>−3</sup>) to the epitaxial layer (~10<sup>16</sup> cm<sup>−3</sup>), the LOPC peak showed a blue shift. The twice travel of the photon (excitation and collection) through the ion-implanted layer with doping concentrations higher than 1 × 10<sup>18</sup> cm<sup>−3</sup> led to a difference in the LOPC peak position for samples with the same epitaxial layer and substrate layer. Furthermore, the influences of the setup in terms of pinhole size and numerical aperture of objective lens on the depth profiling results were studied. Different from other research on Raman depth profiling, the 50× long working distance objective lens (50L× lens) was found more suitable than the 100× lens for the depth analysis 4H−SiC with a multi-layer structure. |
topic |
depth profiling confocal raman spectroscopy silicon carbide lopc mode (longitudinal optical phonon-plasmon coupled mode) |
url |
https://www.mdpi.com/2073-4352/10/2/131 |
work_keys_str_mv |
AT yingsong depthprofilingofionimplanted4hsicusingconfocalramanspectroscopy AT zongweixu depthprofilingofionimplanted4hsicusingconfocalramanspectroscopy AT taoliu depthprofilingofionimplanted4hsicusingconfocalramanspectroscopy AT mathiasrommel depthprofilingofionimplanted4hsicusingconfocalramanspectroscopy AT hongwang depthprofilingofionimplanted4hsicusingconfocalramanspectroscopy AT yufangwang depthprofilingofionimplanted4hsicusingconfocalramanspectroscopy AT fengzhoufang depthprofilingofionimplanted4hsicusingconfocalramanspectroscopy |
_version_ |
1724621967009513472 |