Topic 1: Perfectly Ordered Nanoporous Low-k Dielectrics Formed by Proximity-Field Nanopatterning
Speakers: Qing Cao and Pingfeng Wang
Abstract: Parasitic capacitance formed between interconnect lines is a critical contributor toward the resistive-capacitive delay. Currently, nanoporous SiCOH films are used as low-k interlayer dielectrics. They have random porous structures generated by the release of porogens. The film porosity is in the range of 20-30% to enable dielectric constant (k) down to 2.45. For future technology nodes, extremely low-k dielectrics with k<2.2 are required. However, it is very difficult to achieve this target through simply further increasing SiCOH film’s porosity. In this presentation, we will showcase our research in perfectly ordered porous structures that potentially overcome the limitations of existing dielectrics. We have developed a novel proximity-field nanopatterning technique to build perfectly ordered porous dielectrics with precisely defined 3D nano-architects. The high degree of porosity up to 57% and the uniform architecture enable ultralow k-value of 1.6 and strong mechanical strength with effective modulus up to 31 GPa.
Topic 2: Deposition and patterning of novel dielectric and metal films by low temperature, vuv photochemical processes
Speakers: Gary Eden and Andrey Mironov
Abstract: Virtually all deposition and etching processes employed in the fabrication of electronic and photonic devices are designed to proceed at thermal equilibrium. Relying on thermal equilibrium processes, such as CVD and MBE, for film deposition, for example, compels one to operate at temperatures typically well beyond 400 °C in order to dissociate precursors and provide sufficient adatom mobility. A preferable approach to thin film deposition, for example, is to selectively break precursor chemical bonds with photons. It is the vacuum ultraviolet (VUV) spectral region in which photon energies exceed the energies of all chemical bonds and, since photon energies are well-defined, the chemistry at the substrate surface can be driven far from thermal equilibrium and the substrate temperature reduced significantly. In this presentation, we will focus on film processing chemistry far from thermal equilibrium with hybrid VUV lamp/microplasma processes so as to realize materials having properties superior to those obtainable by conventional thermal processes alone.
Our ability to control film composition and structure apart from substrate temperature opens the door to a broader range of materials than has been available in the past. Mixing of engineered precursors (i.e., bond energies matched to photon sources) and film deposition at dramatically reduced temperatures allows for only the atoms or molecular fragments of interest to be deposited in the absence of spurious species which degrade film characteristics as impurities. Reduced processing temperatures are also a boon to 3D integration because layer-mixing is suppressed.
Topic 3: Topological semi-metals: A potential solution to resistance scaling limitations and spin-orbit torque characterization
Speakers: Yingjie Zhang and Axel Hoffmann
Abstract: A grand challenge in further metal-interconnect scaling is the undesirable resistivity scaling due to increased surface and interface scattering in traditionally used metallic materials systems. Topological Weyl semimetals, which have high conductivity surface states that are robust against disorder, offer a solution for overcoming the resistance scaling limitations of on-chip interconnects. Moreover, the strong spin-orbit coupling and reduced crystal symmetries endow Weyl semimetals with intriguing magnetoelectric effects that can be used for magnetization manipulation in spintronics devices. This talk will focus on the team’s effort dedicated to the fabrication and characterization of Weyl semimetals (TaAs, NbAs, TaP and NbP), Dirac semimetals (Cd3As2, Na3Bi, and ZrTe5), and other unconventional topological semimetals such as WC and MoP. We will also briefly discuss prospects of topological semi-metals for neuromorphic hardware, computation-in-memory, probabilistic computation, and magnetoelectric spin-orbit logic.
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