Why are MOSFETs used for VLSI IC fabrication instead of JFETs?
The N channel JFET needs a negative voltage on its gate with respect to source therefore this complicates the power supply regime by requiring the addition of a negative rail. Similarly, for a P channel device its gate would have to rise above Vcc to be able to control it. Here's an n channel JFET pictorially: -





As you can see, the voltage on the gate has to be negative to the source in order to control it. Images taken from here