Characteristics of La2O3- and Al2O3-Capped HfO2 Dielectric Metal--Oxide--Semiconductor Field-Effect Transistors Fabricated on (110)-Oriented Silicon Substrates
The influence of the crystal orientation difference between (100) and (110) silicon substrates on characteristics of La 2 O 3 - and Al 2 O 3 -capped HfO 2 dielectric metal--oxide--semiconductor field-effect transistors has been investigated. We observed that the equivalent oxide thickness of the cap...
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| Published in | Jpn J Appl Phys Vol. 50; no. 5; pp. 050201 - 050201-3 |
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| Main Authors | , , , , |
| Format | Journal Article |
| Language | English |
| Published |
The Japan Society of Applied Physics
01.05.2011
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| Online Access | Get full text |
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| Summary: | The influence of the crystal orientation difference between (100) and (110) silicon substrates on characteristics of La 2 O 3 - and Al 2 O 3 -capped HfO 2 dielectric metal--oxide--semiconductor field-effect transistors has been investigated. We observed that the equivalent oxide thickness of the capped devices varies according to the crystal orientation, indicating that the two substrates are not equal in the gate stack scalability within a sub-nanometer regime. We found that the mobility dependency on the crystal orientation is reduced by additional scattering associated with the capping films, suggesting the difficulty to derive maximum benefit from an inherent difference in the mobility depending on the crystal orientation. |
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| Bibliography: | The $V_{\text{fb}}$ and the $C_{\text{g}}$ for the uncapped HfO 2 dielectric MOSFETs fabricated on the (100) and (110) substrates. The values of the $C_{\text{g}}$ are evaluated in inversion at the inversion carrier density, $N_{\text{inv}}$, of $5 \times 10^{12}$ cm -2 . The correlation between the $\delta W_{\text{eff}}$ and the $\delta \mathit{EOT}$ for the La 2 O 3 - and Al 2 O 3 -capped HfO 2 dielectric MOSFETs. The thickness of the capping films varies with the samples. The shaded regions correspond to the levels of silicon's conduction band-edge and mid-gap. The cross-sectional TEM images for the La 2 O 3 -capped HfO 2 dielectric gate stacks that have gone through the gate-first MOSFET process. The depth direction is parallel to $\langle 110\rangle$. The $\mu$ of the MOSFETs in strong inversion at the $N_{\text{inv}}$ of $8 \times 10^{12}$ cm -2 . The channel direction is parallel to $\langle 110\rangle$. (a) A comparison of the $\mu$ between the uncapped and capped devices. (b) The relationship of the $\mu$ between the (100) and (110) devices with varying thickness of the capping films. The electron $\mu$ and the hole $\mu$ are plotted separately. |
| ISSN: | 0021-4922 1347-4065 |
| DOI: | 10.1143/JJAP.50.050201 |