Q. What Are the Differences Between Enhancement And Depletion Mosfet?
Depletion MOSFET:Here a slab of p_type material is formed from a silicon base and referred to as substrate. It is the foundation upon which the device will be constructed. In some cases the substrate is internally connected to a source terminal. Many discrete devices provide an additional terminal labelles SS resulting in a four terminal device. The source and drain terminals are connected through metallic contacts to n doped regions linked by an n channel. The gate is also connected to metallic contact surface but remains insulated from the n channel by a very thin silicon dioxide layer.SiO2 is particular type of insulator referred to as dielectric that sets up opposing electric fields within the dielectric when exposed to an externally applied field.
· When gate to source voltage is set to 0,by direct connection from one terminal to another a current is established through the channel.
· When VGS has been set at negative voltage, it will tend to pressure the electrons towards the p type substrate, the drain current is reduced .
· When VGS has been set at positive voltage the positive gate will draw additional electrons from the p type substrate and hence resulting in increase in current.