L
         _________________________
        /                        /|
       / W      Oxide C         / |
      /                        /  /
     /________________________/  /
     |                        | //|
     |________________________|// |
   T  /        e_r             /  /
     /________________________/  /
     |                        | /
     |________________________|/

 C   = e_r*e_0*Length*Width/Thickness
 e_0 = 8.8541878176 × 10−12 F/m  ( permittivity free space )