Columbia University

Technology Ventures

Large grain silicon thin films produced by excimer laser annealing

Technology #cu14160

Polycrystalline silicon thin film transistors used in active matrix liquid crystal display devices are produced by melting and recrystallization of amorphous silicon. However, the boundaries between silicon crystal grains created during annealing reduce electron mobility, thereby increasing electrical resistance and reducing efficiency. This technology uses an excimer laser annealing method with multiple laser tubes to increase silicon crystal grain size. The larger grain sizes increase electron mobility, improve the performance of silicon thin film transistors, and enable the production of higher quality displays in electronic devices.

Large grain thin film transistors reduce electrical resistance for improved performance

This technology efficiently produces high performance thin film transistors with large grain size using excimer laser annealing. By using multiple laser tubes, this technology achieves higher energy densities than conventional excimer laser annealing. As a result, fewer laser pulses are required for annealing, resulting in the formation of large grain crystal silicon thin films. With reduced electrical resistance and increased electron mobility afforded by large grain crystals, this technology can produce high performance thin film transistors for a multitude of electronic applications.

Lead Inventor:

James Im, Ph.D.


  • Thin film transistors for active matrix liquid crystal displays in flat panel consumer electronics, such as televisions, computer monitors, and mobile devices
  • Semiconductor and transistor fabrication


  • Produces higher energy density than possible with a single laser
  • Produces large grain silicon thin films transistors for high performance displays
  • Reduces silicon thin film electrical resistance
  • Increases silicon thin film electron mobility

Patent Information:

Patent Pending

Tech Ventures Reference: IR CU14160