Difference Between Schottky Contact and Ohmic Contact

Schottky contact means that when a metal and a semiconductor material are in contact, the energy band of the semiconductor is bent at the interface to form a Schottky barrier. The existence of the potential barrier leads to the large interfacial resistance. Corresponding to it is the ohmic contact, where the potential barrier at the interface is very small or there is no contact potential barrier. The following editor will introduce to you "Schottky contact principle, the difference between ohmic contact and Schottky contact"

The principle of Schottky contact

The basic principle is that the work function of semiconductors is generally smaller than that of metals, so when the metal contacts the semiconductor (for example, N-type), electrons flow from the semiconductor into the metal, forming a positively charged non-movable on the surface layer of the semiconductor. The space charge region composed of impurity ions, in which there is an electric field directed from the semiconductor to the metal, is like building a high wall to prevent the electrons in the semiconductor from continuing to flow into the metal. From the Schottky barrier energy band diagram in Figure 1b, it can be seen that the energy band of the semiconductor is bent at the interface to form a high potential energy region, which is the Schottky barrier. Electrons must have energy above this barrier to cross the barrier and flow into the metal. When balanced, the height of the Schottky barrier is the difference between the work functions of the metal and semiconductor.

Second, the difference between ohmic contact and Schottky contact

Ohmic contact means that the metal and semiconductor form an ohmic contact, which means that there is a pure resistance at the contact, and the smaller the resistance, the better, so that when the component is operating, most of the voltage drop is in the active area and not on the contact surface. Therefore, its I-V characteristic is a linear relationship. The larger the slope, the smaller the contact resistance. The size of the contact resistance directly affects the performance index of the device.

Schottky contact means that when a metal and a semiconductor material are in contact, the energy band of the semiconductor is bent at the interface to form a Schottky barrier. The existence of the potential barrier leads to the large interfacial resistance. Corresponding to it is the ohmic contact, where the potential barrier at the interface is very small or there is no contact potential barrier.

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