· Channel Doping
FinFET channel is usually desired to be fully depleted however to have improved control of leakage current under the fins the channel is usually lightly doped 10. The doping concentration of Source and Drain region requires high dopant and hence increases the series resistance of the device 18. This damages the fin’s geometry of the device. To overcome this problem local epitaxial growth is done at the source and drain area with or without removing the fin of the structure 18.
· FinFET Parametric capacitance
FinFETs has more parasitic capacitance than planar structures. The overlap between the front and back gate increases the capacitance of the device. The variation in the Fin height, i.e. the increase in fin height and decrease in fin pitch reduces the capacitance of the device 10.
F. Reliability Concerns of FinFET
Reliability has posed various challenges to device scaling from the earliest days of the semiconductor industry. The need to improve reliability with each successive technology node increases since failure mechanisms of the most common IC degradation increases with successive technology nodes. The continuous scaling of device dimension and the introduction of FinFET technology has led to new reliability concerns, such as Bias Temperature Instability (BTI), Stress-Induced Leakage Current (SILC), Self-Heat Effect (SHE) and Time Dependent Junction degradation (TDJD) 19. These reliability issues become manufacturing, process and design bottleneck for the advanced technology development because of their stringent process requirements and the device trade-off 19.
FinFET is a promising technology alternative to the next generation devices than conventional planar MOSFET which has reached its scaling limits and is too leaky for too little performance gain. FinFET is currently being used as the basis for semiconductor fabrication because of its power and performance benefits, scalability, superior controls over short channel effects etc. Almost all the major Integrated device manufacturers in the semiconductor eco-system are focusing and putting lot of efforts on this promising and disruptive technology. It provides a new pathway for Moore’s Law beyond 22nm as they have much better performance and reduced power consumption compared to planar transistors.