Theoretical Shape of Metal‐Insulator‐Metal Potential Barriers

The shape of metal‐insulator‐metal potential barriers is derived, including the effects of space charge. For very thin insulating films, the barrier is shown to be essentially rectangular (or trapezoidal if different metals are used on either side of the insulating film). The modification in the rectangular barrier introduced by image forces is derived and shown to be significant for very thin insulating films. Finally, the effect of insulator doping on barrier shape is considered.