Session 36: Modeling and Simulation Materials and Interfaces

Wednesday, December 7, 1:30 p.m.
Continental Ballroom 7-9
Co-Chairs: Chung-Cheng Wu, TSMC
Masumi Saitoh, Toshiba

1:35 PM
36.1 Surface Roughness Limited Mobility in muti-gate FETs with Arbitrary Cross-section, O. Badami, D. Lizzit, R. Specogna and D. Esseni, University of Udine

This paper presents the derivation, implementation and validation of a new model for Surface Roughness Scattering (SRS) in multi-gate FETs (MuGFETs) and gate-all-around nanowires (GAA-NW) FETs. The model employs a non linear relation between SRS matrix elements and interface fluctuations, that in planar MOSFETs allowed us to reconcile mobility simulations with experimental values for the r.m.s. interface roughness \Delta_{rms}\ \cite{Lizzit_JAP2014,Oves_TED2017}. The model is formulated for fairly arbitrary cross-sections and biasing conditions.

2:00 PM
36.2 Nitridation of GaN Surface for Power Device Application: A First-Principles Study, Z. Zhang, B. Li, X. Tang, Q. Qian, M. Hua, B. Huang and K. J. Chen, The Hong Kong University of Science and Technology

The effects of nitridation on GaN surface in the context of surface state distribution are investigated by first-principles calculation and XPS/UPS verification. The surface modification explains the significantly improved interface quality in GaN MIS-/MOS-structures featuring nitridation interfacial layer, and also provides evidence to support a physical model for the GaN band-edge emission in metal-AlGaN/GaN Schottky heterojunction.

2:25 PM
36.3 Manipulating Spin Polarization and Carrier Mobility in Zigzag Graphene Ribbons using an Electric Field (Invited), C. Delerue, J. Li* and Y.-M. Niquet**, IEMN-UMR CNRS, *Grenoble Alpes University, CNRS, **Grenoble Alpes University, CEA, INAC-SP2M

We present atomistic calculations of the band structure and the phonon-limited carrier transport properties of zigzag graphene nanoribbons. We show that a lateral electric field can be used to tune the carrier mobility and mean free path over orders of magnitude and to change the spin polarization of the current. These effects could be nicely exploited in electronic and spintronic devices.

2:50 PM
36.4 Density Functional Theory Simulations and Experimental Measurements of a-HfO2/a-Si3N4/SiGe, a-HfO2/SiO0.8N0.8/SiGe and a-HfO2/a-SiO/SiGe Interfaces., E. Chagarov, K. Sardashti, M. Edmonds, M. Clemons and A. Kummel, University of California, San Diego

A comprehensive set of density functional theory (DFT) molecular dynamics (MD) simulations is presented for interfaces between a-HfO2 high-K oxide and Si0.5Ge0.5(001) with several amorphous stoichiometric and sub-stoichiometric SiOxNy interlayers (a-SiO0.8N0.8, a-SiO0.4N0.4, a-Si3N2, a-Si3N4 and a-SiO) to determine their electrical passivation properties. In general the sub-stoichiometric interlayers had superior electrical properties because they minimized Ge-O and Ge-N bond formation and had low internal bond strain. The stack with oxygen deficient a-SiO interlayer demonstrated superior electric properties because it avoided all dangling bond formation. Experimental studies confirmed that a sub-stiochiometric SiON layer decreases the defects density of HfO2(001)/Si0.5Ge0.5(001) MOCAPs.

3:15 PM
36.5 Insight into PBTI in InGaAs Nanowire FETs with Al2O3 and LaAlO3 Gate Dielectrics, Y. Li, S. Di, H. Jiang, P. Huang, Y. Wang, Z. Lun, L. Shen, L. Yin, X. Zhang, G. Du and X. Liu, Peking University

The traps induced degradation of the Al2O3 and LaAlO3 based InGaAs nanowire FETs are investigated by 3D KMC method considering trap coupling and trap generation. The measurement time constants of the defect in Al2O3 and PBTI can be well interpreted by consideration with metastable state. The power law of threshold shift can be greatly affected by the stress. Different from Al2O3 oxygen vacancies and interstitial Aluminum ions in LaAlO3 have important roles in PBTI. Simulated results indicate that Al2O3 have better PBTI and recovery than that of LaAlO3.

3:40 PM
36.6 Contact Resistivities in Gamma-valley Materials, P. Solomon, IBM T.J Watson Research Center

A model for contact resistivities of materials such as n-type III-V semiconductors with gamma-valley symmetry is developed which goes beyond current models in including non-parabolicity and screening effect of electrons on the Schottky barrier. These raise the contact resistivity, so that strategies involving negative barrier heights and interface velocity matching may be necessary to reach ITRS targets.

4:05 PM
36.7 TCAD-based Investigation on Transport Properties of Diamond-like Carbon Coatings for HV-ICs, S. Reggiani, C. Giordano, A. Gnudi, E. Gnani, G. Baccarani, J. Dobrzynska*, J. Vobecky* and M. Bellini**, Università di Bologna, *ABB Semiconductors Ltd., **ABB Switzerland

A TCAD-based approach is proposed to investigate the most relevant transport mechanisms of diamond-like carbon (DLC) films at different biases and ambient temperatures. Starting from the band structure and boundary conditions of a metal-insulator-metal (MIM) device, the most relevant trap levels have been determined against experiments along with the Poole- Frenkel conduction effect. The affinity of the DLC under study has been extracted from experiments on the corresponding metal-insulator-semiconductor (MIS) diode. A clear polarization effect has been found in the measured C-V curves at different frequencies. The latter has been modeled in the TCAD tool via the Debye equation leading to a nice agreement with experiments.