Defying the isotropic nature of traditional chemical etch, metal-assisted chemical etching (MacEtch) has allowed spatially defined anisotropic etching by using patterned metal catalyst films to locally enhance the etch rate of various semiconductors. Significant progress has been made on achieving unprecedented aspect ratio nanostructures using this facile approach, mostly in solution. However, the path to manufacturing scalability remains challenging because of the difficulties in controlling etch morphology (e.g., porosity and aggregation) and etch rate uniformity over a large area. Here, we report the first programmable vapor-phase MacEtch (VP-MacEtch) approach, with independent control of the etchant flow rates, injection and pulse time, and chamber pressure. In addition, another degree of freedom, light irradiation is integrated to allow photo-enhanced VP-MacEtch. Various silicon nanostructures are demonstrated with each of these parameters systematically varied synchronously or asynchronously, positioning MacEtch as a manufacturing technique for versatile arrays of three-dimensional silicon nanostructures. This work represents a critical step or a major milestone in the development of silicon MacEtch technology and also establishes the foundation for VP-MacEtch of compound semiconductors and related heterojunctions, for lasting impact on damage-free 3D electronic, photonic, quantum, and biomedical devices.
Metal‐assisted chemical etching (MacEtch) has shown tremendous success as an anisotropic wet etching method to produce ultrahigh aspect ratio semiconductor nanowire arrays, where a metal mesh pattern serves as the catalyst. However, producing vertical via arrays using MacEtch, which requires a pattern of discrete metal disks as the catalyst, has often been challenging because of the detouring of individual catalyst disks off the vertical path while descending, especially at submicron scales. Here, the realization of ordered, vertical, and high aspect ratio silicon via arrays by MacEtch is reported, with diameters scaled from 900 all the way down to sub‐100 nm. Systematic variation of the diameter and pitch of the metal catalyst pattern and the etching solution composition allows the extraction of a physical model that, for the first time, clearly reveals the roles of the two fundamental kinetic mechanisms in MacEtch, carrier generation and mass transport. Ordered submicron diameter silicon via arrays with record aspect ratio are produced, which can directly impact the through‐silicon‐via technology, high density storage, photonic crystal membrane, and other related applications.
more » « less- PAR ID:
- 10034131
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Functional Materials
- Volume:
- 27
- Issue:
- 12
- ISSN:
- 1616-301X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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