Tunnel field-effect transistors

[kevinisfrom]

Hi All,

I've been reading about tunnel field-effect transistors (TFET) as a potential design to impact post-CMOS technologies, however I'm having a hard time understanding the idea and also some of the terminology. For example, what is a p-i-n TFET? I understand that one side has to be p-doped, the other side is n-doped and the middle is an insulator, but how does changing the gate voltage induce an on/off state? The gate is over an insulator, which means the Fermi level should not change. And why is there a need for two gates? I've also read that MOFETs have thermionic current while TFETs use tunneling current - what's the difference between the two?

Thanks in advance for all the help!

 

[anorlunda]

The answers are found at

https://en.wikipedia.org/wiki/Tunnel_field-effect_transistor

The basic TFET structure is similar to a MOSFET except that the source and drain terminals of a TFET are doped of opposite type (see figure). A common TFET device structure consists of a P-I-N (p-type, intrinsic, n-type) junction, in which the electrostatic potential of the intrinsic region is controlled by a gate terminal.