How do N-channel MOSFETs work?

In the planar MOSFET shown below:

1.     Apply voltage between drain and source in positive polarity. (Drain-source voltage: V_DS)

2.     Apply voltage between gate and source in positive polarity. (Gate-source voltage: V_GS)

3.     As a result, electrons are attracted to P layer under a gate insulator film and P layer becomes N layer. (Such P layer that becomes N layer is called an “inversion layer.”)

4.     All regions of MOSFET become N layer (from drain side: “N+”-”N-”-”inversion layer(N)”– “N+”) due to inversion mentioned in 3.

5.     As a result, MOSFET works as a resistor, and drain current determined by applied V_DS and load flows.