Paper VT-ThP13
Custom-Designed Very-High Vacuum Chamber for Growth of Large Area Silicon Nanowhiskers Arrays via an Ion-Enhanced Vapor-Liquid-Solid (VLS) Mechanism

Thursday, October 18, 2007, 5:30 pm, Room 4C

A VHV chamber was custom-designed for experimental growth of silicon nanowhisker arrays via a novel ion-enhanced Vapor-Liquid-Solid (VLS) technique. Growth was to be carried out on a self-organized metal seed layer on a Si or SiO₂ surface. A reactive magnetron sputtering system was needed to supply atomic Si to the growth surface under concurrent high-energy ion irradiation. The successful implementation of this growth technique required sample temperature control to 450°C, a bias voltage up to 3kV, and a reactive plasma environment. Additional deposition capabilities and process controls for several inert and reactive gases were also required. The design goal was to develop an economical system using standard vacuum hardware that allowed handling of two-inch Si wafers. A wafer stage using a halogen reflector bulb for temperature control was designed to meet the requirements for whisker growth. Protection of the insulators and wafer handling proved to be especially challenging during the design of this stage. The chamber design also included capabilities for wafer storage and wafer transfer between two DC magnetron sputtering stations and a miniature evaporator custom-designed to fit a 2³/₄-flange. This presentation will describe the realization of the chamber design, which made possible the processing of nearly four hundred samples to date. Ultimately, this enabled the growth of aligned Si nanowhisker arrays at temperatures below 200 °C and at rates up to 200 nm/min. Growth can take place on any substrate on which a thin Si film can be deposited.