Let%27s explore how doping concentration impacts the performance of MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors).
1. Threshold Voltage (VTH) and Leakage Current (Ioff):
- Increasing the doping concentration in the MOSFET channel has specific effects:
- Threshold Voltage (VTH): As the doping concentration increases, the threshold voltage tends to rise. This means that a higher gate voltage is required to turn the MOSFET on.
- Leakage Current (Ioff): Conversely, higher doping concentrations lead to a reduction in leakage current when the MOSFET is in the off-state. Lower leakage current is desirable for power efficiency.
2. Carrier Mobility and Switching Speed:
- Carrier mobility refers to how quickly charge carriers (electrons or holes) move through the channel.
- Higher doping concentrations can impact carrier mobility:
- Decreased Carrier Mobility: When doping concentration increases significantly, carrier mobility may decrease. This results in slower switching speeds because carriers move less efficiently.
- Increased Threshold Voltage: As mentioned earlier, higher doping concentrations raise the threshold voltage. This can lead to faster switching speeds because the MOSFET transitions from off to on more rapidly.
3. Junctionless (JL) Multigate Transistors:
- To address challenges posed by scaling and nanometer-sized transistors, researchers have proposed Junctionless multigate transistors.
- These devices eliminate the traditional channel junction and rely on varying doping concentrations along the channel.
- By precisely controlling doping profiles, JL multigate transistors aim to achieve better performance while maintaining scalability.
In summary, doping concentration plays a critical role in MOSFET behavior. Designers must strike a balance to optimize performance, minimize leakage, and enhance switching speed based on specific application requirements¹²³.
(1) Design and Performance Analysis of Advanced MOSFET Structures - Springer. https://link.springer.com/article/10.1007/s42341-021-00338-9.
(2) Study the effect of channel doping concentration on electrical .... https://pubs.aip.org/aip/acp/article/2306/1/020005/749332/Study-the-effect-of-channel-doping-concentration.
(3) How does doping concentration affect MOSFET switching speed?. https://electronics.stackexchange.com/questions/483907/how-does-doping-concentration-affect-mosfet-switching-speed.
(4) Impact of Doping Concentration on the performance of TMG Re-S/D FDSOI .... https://ieeexplore.ieee.org/document/8596870.
(5) Graded channel doping junctionless MOSFET: a potential high performance .... https://link.springer.com/article/10.1007/s10825-017-1052-1.
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