New Etching Methodologies for Atomic Level Precision in Manufacturing Processes at the Micro-to-Nanoscale

University Of Delaware, Newark DE

Investigators

Abstract

This grant develops new etching methods to meet the increasingly demanding needs in fabricating nanoscale devices within the semiconductor industry. The fabrication of novel and advanced devices requires atomically precise removal of materials in a stack of complex thin films, each of several nanometers thick, while maintaining surface smoothness and material properties. The atomic layer etching (ALE) has emerged as the most reliable method to remove materials one atomic layer at a time. This overall novel strategy has been relatively well understood for single element materials; however, the major challenge in practical applications, such as memory, logic devices, processing and information transfer, requires etching of alloys and heterostructures. This grant seeks the fundamental knowledge needed to extend the ALE technology to process alloys and heterostructures with atomic precision. The studies may also solve a number of hurdles to pushing the boundary of advanced manufacturing beyond silicon electronics. The multidisciplinary approach required to tackle these problems will offer advanced training opportunities in crossing fields of physics, chemistry, materials science, and engineering, and will advance the participation of underrepresented groups in science and technology disciplines. The research supported by this grant will combine thermal chemical etching, materials physics, and device design to overcome the limitations of current technologies in (1) selective etching of complex alloy materials consisting of two or more metals and light elements, (2) self-termination at target oxide layers, and (3) precision etching of thick oxide layers to achieve non-tapered vertical edges. The research team will use analytical spectroscopy and microscopy methods together with computer modeling to determine kinetic and thermodynamic factors responsible for the etching rates of specific elements and combine them to define the strategy for atomic precision etching of complex materials. This strategy is based on selecting appropriate chemical ligands that bind to each element of the films selectively and determining the parameters for designing etching cycles that can remove the materials layer-by-layer without altering the concentration of the elements and morphology of the surface. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.