Uniform square polycrystalline silicon fabricated by employing periodic metallic pads and SiON absorption layer for thin film transistors
Journal
IEEE Transactions on Electron Devices
Journal Volume
55
Journal Issue
8
Pages
2212-2217
Date Issued
2008
Author(s)
Abstract
The polycrystalline silicon with regular square grains is fabricated by employing metallic (Cr/Al) periodic pads as the heat sinks and with underlying silicon oxynitride (SiON) as the heat absorption layer. The maximum lateral growth length of the poly-Si is 1.78 μm by this method. If the metal pads are periodically arranged, the poly-Si can grow to regular square grains following the high power excimer laser annealing. After removing the metallic pads, the low power laser shot transfers the a-Si:H under the original metallic pads to poly-Si without destroying the square grains. The TFTs fabricated by this method achieve a field effect mobility of 450 cm2/V· s and an on/off current ratio exceeding 107. It is found that the TFT with smaller channel width and length results in a better subthreshold swing because it contains fewer grain boundaries and defects. © 2008 IEEE.
Subjects
Polycrystalline silicon; Thin film transistor (TFT)
Other Subjects
Absorption; Amorphous materials; Annealing; Excimer lasers; Gas lasers; Heat storage; Lasers; Metallic soaps; Metals; Nitrides; Nonmetals; Optical design; Polysilicon; Silicon carbide; Thick films; Thin film devices; Thin film transistors; Transistors; Absorption layers; Excimer-laser annealing; Field-effect mobilities; Heat absorption; High powers; Lateral growth; Low-power lasers; Metal pads; Metallic pads; Poly-Si; Polycrystalline silicon; Silicon Carbide devices; Silicon oxynitride; Thin film transistor (TFT); Silicon
Type
journal article