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Problem:
- ON/OFF ratio of tunnel field-effect transistors (TFETs) is limited by
- low source-to-channel tunneling probability.
- high source-to-drain tunneling leakage.
- Lowering the drain doping density (Nd) suppresses the leakage but is not scable.
- The source-pocket (SP) design improves the tunnel probability but requires a high pocket doping density (Np)
Objective:
- To explore different channel doping strategies to improve ON current of TFETs
Approaches:
- D1, a conventional nTFET with intrinsic channel
- D2, intrinsic channel with a P+ drain pocket
- D3, P+ channel with an intrinsic source pocket
- D4, P+ channel with an N+ source pocket
Results/Impact:
- D2 improves the subthreshold swing (and ION) and it is more scalable than lowering Nd
- D3 performs similarly to the SP design
- D4 further improves ION of the SP design without having to increase Np
- D2, D3, and D4 improve the ION of D1 from 25A/m to 43A/m, 114A/m, and 170A/m, respectively, at IOFF=10^-3A/m and VDD=0.3V
- in Proc. 74th Annu. Device Res. Conf. (DRC), Jun. 2016.
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