I have been confused by this question: why is NMOS substrate lightly doped? Why is it necessary for MOSFETs but not for TFTs? Can anybody help me? Thanks!

 

Welcome to AAC!

Different manufacturing techniques.

TFT's are made by depositing material on an insulator and the insulator provides isolation for the transistors.

For IC's, all of the transistors are produced on the same substrate and devices need to be separated by the relatively high resistance of the substrate and by putting implants between transistors to isolate them.

 

Welcome to AAC!

Different manufacturing techniques.

TFT's are made by depositing material on an insulator and the insulator provides isolation for the transistors.

For IC's, all of the transistors are produced on the same substrate and devices need to be separated by the relatively high resistance of the substrate and by putting implants between transistors to isolate them.

Thanks for your reply! Is it that a p-n junction is formed between an nMOS and a pMOS so that there is an energy barrier to decrease the carrier flow between the two components, and also between the components and the substrate?