Question

Explain the structure pmos enhancement transistor

Answer 1

MOSFET which has p - channel region between source any gate is known as p - channel MOSFET. It is a four terminal devices, the terminals are gate, drain, source and substrate or body. The drain and source are heavily doped p+ region and the substrate is in n-type. The current flows due to the flow of positively charged holes that’s why it is known as p-channel MOSFET. When we apply negative gate voltage, the electrons present beneath the oxide layer, experiences repulsive force and they are pushed downward in to the substrate, the depletion region is populated by the bound positive charges which are associated with the donor atoms. The negative gate voltage also attracts holes from p+ source and drain region in to the channel region. Thus hole which channel is formed now if a voltage between the source and the drain is applied current flows. The gate voltage controls the hole concentration of the channel.