Carrier generation and current flow at the interface between polysilicon and an SiO2 gate dielectric

✍ Scribed by W. Eccleston

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 81 KB
• Volume: 59
• Category: Article
• ISSN: 0167-9317
• DOI: 10.1016/s0167-9317(01)00613-x

✦ Synopsis

Polycrystalline materials are important for a range of modern devices including CMOS transistors. There is a need to understand carrier generation and flow in such materials. Polysilicon TFTs are used to test a model based on generation in grain boundaries. When the generation is stimulated by the depletion of the material, due to the field effect, carriers are drawn to the surface and move along it by a process akin to diffusion. At some gate voltage the supply of carriers to the channel is insufficient to maintain the current flow. This leads to a reverse bias across the drain junction. The temperature dependence of currents at the current minimum, and at current saturation, of the transfer characteristic are described and are used to justify the model for generation and current flow.