Flexible field-effect transistors using top-down fabrication of (111)-silicon nanowires and wafer-level transfer process for neural prostheses

•A simple fabrication method and a large-scale integration of silicon nanowires by combining top-down fabrication with wafer-level transfer process on a flexible substrate.•The proposed method can implement the width and thickness of silicon nanowires independently, which can result in higher performance characteristics.•The overall device thickness is sufficiently thin for high device flexibility.•The quantitative current model is used to analyze the operation mechanism of silicon-nanowire FET.

In this paper, a simple fabrication method and a large-scale integration of silicon nanowires by combining top-down fabrication with wafer-level transfer process on a flexible substrate is presented. For applications in high-resolution neural prostheses, silicon-nanowire field-effect transistor (FET) switches on a flexible substrate is developed and integrated to microelectrode array (MEA). The fabrication process is developed, and results of (111)-silicon nanowire array and nanowire devices on flexible substrate are shown. The overall device thickness is sufficiently thin for high device flexibility. The quantitative current model is used to analyze the operation mechanism of silicon-nanowire FET. The proposed method can implement the width and thickness of silicon nanowires independently, which can result in higher performance characteristics. The electrical characteristics of the fabricated silicon-nanowire FET switch are measured. The current on/off ratio is above 1 × 107 and average RON is calculated to be 41 kΩ, which shows similar results with the simulation. These results of proposed method show a strong potential for applications in high-resolution neural prostheses.

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