Flexible silicon expands application possibilities

Single-crystal semiconductor materials such as silicon (Si) and gallium arsenide have previously been transferred to flexible polymers to create thin-film transistors (TFTs) on plastic; however, the process is limited and cumbersome.

Th 0610lfw Nwsbk1

Single-crystal semiconductor materials such as silicon (Si) and gallium arsenide have previously been transferred to flexible polymers to create thin-film transistors (TFTs) on plastic; however, the process is limited and cumbersome. Researchers at the University of Wisconsin-Madison (Madison, WI) have instead developed a simpler, more versatile transfer technique that allows them to create strained-silicon TFTs with high drive current and high transconductance, making them excellent candidates for use in displays, solar cells, and biosystem implants.

Th 0610lfw Nwsbk1
Click here to enlarge image

The TFT active layer is formed as a thin membrane on silicon-on-insulator (SOI) substrates. Both strained- and unstrained-silicon TFTs are fabricated in a similar process using a sandwich structure of Si and silicon-germanium alloy. Photolithography is used to pattern the membrane, which is then transferred (using a “dry” printing method) to a flexible polyethylene substrate onto which a layer of photoresist has been applied that serves as both an adhesive and as the gate-dielectric layer for the TFTs. Contact Zhenqiang Ma at [email protected].

More in Research