In-situ MOCVD Growth and Band Offsets of Al$_2$O$_3$ Dielectric on $β$-Ga$_2$O$_3$ and $β$-(Al$_x$Ga$_{1-x}$)$_2$O$_3$ thin films
Fuente:
arXiv
Saved in:
| Main Authors: | , , , , |
|---|---|
| Format: | Preprint |
| Published: |
2022
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866915097652232192 |
|---|---|
| author | Bhuiyan, A F M Anhar Uddin Meng, Lingyu Huang, Hsien-Lien Hwang, Jinwoo Zhao, Hongping |
| author_facet | Bhuiyan, A F M Anhar Uddin Meng, Lingyu Huang, Hsien-Lien Hwang, Jinwoo Zhao, Hongping |
| contents | The in-situ metalorganic chemical vapor deposition (MOCVD) growth of Al$_2$O$_3$ dielectrics on $β$-Ga$_2$O$_3$ and $β$-(Al$_x$Ga$_{1-x}$)$_2$O$_3$ films is investigated as a function of crystal orientations and Al compositions of $β$-(Al$_x$Ga$_{1-x}$)$_2$O$_3$ films. The interface and film qualities of Al$_2$O$_3$ dielectrics are evaluated by high resolution X-ray diffraction (HR-XRD) and scanning transmission electron microscopy (HR-STEM) imaging, which indicate the growth of high quality amorphous Al$_2$O$_3$ dielectrics with abrupt interfaces on (010), (100) and (-201) oriented $β$-(Al$_x$Ga$_{1-x}$)$_2$O$_3$ films. The surface stoichiometries of Al$_2$O$_3$ deposited on all orientations of $β$-(Al$_x$Ga$_{1-x}$)$_2$O$_3$ are found to be well maintained with a bandgap energy of 6.91 eV as evaluated by high resolution x-ray photoelectron spectroscopy, which is consistent with the atomic layer deposited (ALD) Al$_2$O$_3$ dielectrics. The evolution of band offsets at both in-situ MOCVD and ex-situ ALD deposited Al$_2$O$_3$/$β$-(Al$_x$Ga$_{1-x}$)$_2$O$_3$ are determined as a function of Al composition, indicating the influence of the deposition method, orientation, and Al composition of $β$-(Al$_x$Ga$_{1-x}$)$_2$O$_3$ films on resulting band alignments. Type II band alignments are determined at the MOCVD grown Al$_2$O$_3$/$β$-(Al$_x$Ga$_{1-x}$)$_2$O$_3$ interfaces for (010) and (100) orientations, whereas type I band alignments with relatively lower conduction band offsets are observed along (-201) orientation. Results from this work revealed that the in-situ MOCVD deposited high quality Al$_2$O$_3$ dielectrics with sharp interfaces can be considered as a viable alternative of commonly used ex-situ deposited (ALD) Al$_2$O$_3$ for developing high performance $β$-Ga$_2$O$_3$ and $β$-(Al$_x$Ga$_{1-x}$)$_2$O$_3$ based devices. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2207_13001 |
| institution | arXiv |
| publishDate | 2022 |
| record_format | arxiv |
| spellingShingle | In-situ MOCVD Growth and Band Offsets of Al$_2$O$_3$ Dielectric on $β$-Ga$_2$O$_3$ and $β$-(Al$_x$Ga$_{1-x}$)$_2$O$_3$ thin films Bhuiyan, A F M Anhar Uddin Meng, Lingyu Huang, Hsien-Lien Hwang, Jinwoo Zhao, Hongping Materials Science The in-situ metalorganic chemical vapor deposition (MOCVD) growth of Al$_2$O$_3$ dielectrics on $β$-Ga$_2$O$_3$ and $β$-(Al$_x$Ga$_{1-x}$)$_2$O$_3$ films is investigated as a function of crystal orientations and Al compositions of $β$-(Al$_x$Ga$_{1-x}$)$_2$O$_3$ films. The interface and film qualities of Al$_2$O$_3$ dielectrics are evaluated by high resolution X-ray diffraction (HR-XRD) and scanning transmission electron microscopy (HR-STEM) imaging, which indicate the growth of high quality amorphous Al$_2$O$_3$ dielectrics with abrupt interfaces on (010), (100) and (-201) oriented $β$-(Al$_x$Ga$_{1-x}$)$_2$O$_3$ films. The surface stoichiometries of Al$_2$O$_3$ deposited on all orientations of $β$-(Al$_x$Ga$_{1-x}$)$_2$O$_3$ are found to be well maintained with a bandgap energy of 6.91 eV as evaluated by high resolution x-ray photoelectron spectroscopy, which is consistent with the atomic layer deposited (ALD) Al$_2$O$_3$ dielectrics. The evolution of band offsets at both in-situ MOCVD and ex-situ ALD deposited Al$_2$O$_3$/$β$-(Al$_x$Ga$_{1-x}$)$_2$O$_3$ are determined as a function of Al composition, indicating the influence of the deposition method, orientation, and Al composition of $β$-(Al$_x$Ga$_{1-x}$)$_2$O$_3$ films on resulting band alignments. Type II band alignments are determined at the MOCVD grown Al$_2$O$_3$/$β$-(Al$_x$Ga$_{1-x}$)$_2$O$_3$ interfaces for (010) and (100) orientations, whereas type I band alignments with relatively lower conduction band offsets are observed along (-201) orientation. Results from this work revealed that the in-situ MOCVD deposited high quality Al$_2$O$_3$ dielectrics with sharp interfaces can be considered as a viable alternative of commonly used ex-situ deposited (ALD) Al$_2$O$_3$ for developing high performance $β$-Ga$_2$O$_3$ and $β$-(Al$_x$Ga$_{1-x}$)$_2$O$_3$ based devices. |
| title | In-situ MOCVD Growth and Band Offsets of Al$_2$O$_3$ Dielectric on $β$-Ga$_2$O$_3$ and $β$-(Al$_x$Ga$_{1-x}$)$_2$O$_3$ thin films |
| topic | Materials Science |
| url | https://arxiv.org/abs/2207.13001 |