| Autor: |
Honggyun Kim, Vijay D. Chavan, Jamal Aziz, Byoungsu Ko, Jae-Sung Lee, Junsuk Rho, Tukaram D. Dongale, Kyeong-Keun Choi, Deok-Kee Kim |
| Jazyk: |
angličtina |
| Rok vydání: |
2022 |
| Předmět: |
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| Zdroj: |
IEEE Access, Vol 10, Pp 68724-68730 (2022) |
| Druh dokumentu: |
article |
| ISSN: |
2169-3536 |
| DOI: |
10.1109/ACCESS.2022.3183593 |
| Popis: |
The surface passivation of a CMOS image sensor (CIS) is highly beneficial for the overall improvement of a device performance. We employed the thermal atomic layer deposition (T-ALD) and plasma enhanced (PE-ALD) techniques for the deposition of 20 nm HfO2 as well as stacked with 3 and 5 nm Al2O3 thin films. The HfO2/Si and Al2O3/HfO2/Si metal-oxide-semiconductor structures were used to analyze the fixed charge density ( $\text{Q}_{\mathrm {f}}$ ) and interface trap density ( $\text{D}_{\mathrm {it}}$ ). The as-synthesized samples show high $\text{D}_{\mathrm {it}}$ and $\text{Q}_{\mathrm {f}}$ values (1012 cm−2eV−1) and a minority carrier lifetime of 15–300 $\mu \text{s}$ . The finite-difference time-domain simulation of high-k dielectrics confirmed that the Al2O3 (top)/HfO2 stacked structures expected higher quantum efficiency for CIS application. The effect of vacuum annealing (VA) and forming gas annealing (FGA) treatments succeeded with the decomposition of the $\text{D}_{\mathrm {it}}$ and increase in carrier lifetime. The H2 ambient FGA samples showed a remarkable decrease in the $\text{D}_{\mathrm {it}}$ values. To improve the overall performance of the device after passivation, we employed an Al2O3/HfO2 bilayer structure, which showed a low $\text{D}_{\mathrm {it}}$ of 1011 cm−2eV−1 and a minority carrier lifetime of $\sim 3$ ,700 $\mu \text{s}$ after 400 °C and 30 min FGA. We believe that this surface passivation strategy will pave way for future CIS technology regarding the development of lower defective surface and superior performance. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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