What are semiconductor contacts?

The metal-semiconductor (MS) contact is an important component in the performance of most semiconductor devices in the solid state. As the name implies, the MS junction is that a metal and a semiconductor material are contacted closely.

When a metal is in contact with a semiconductor?

On the other hand, when a contact is formed between a metal and semiconductor, due to the low charge density on the semiconductor side (typically 1017 cm-3) the electrons are removed not only from the surface 6 Page 7 NOC: Fundamentals of electronic materials and devices Figure 6: Schottky junction between metal and n- …

What are Schottky contacts?

The rectifying contact that occur between a metal and a lightly doped semiconductor. b) Ideal energy -band diagram of a metal and n-type semiconductor junction. …

What is contact resistance in semiconductor?

Contact resistance is a measure of the ease with which current can flow across a metal- semiconductor interface. In an ohmic interface, the total current density J entering the interface is a function of the difference in the equilibrium Fermi levels on the two sides.

What is metal semiconductor diode?

In solid-state physics, a metal–semiconductor (M–S) junction is a type of electrical junction in which a metal comes in close contact with a semiconductor material. Occasionally however a Schottky barrier is useful, as in Schottky diodes, Schottky transistors, and metal–semiconductor field effect transistors.

What metals are used in semiconductors?

The most used semiconductor materials are silicon, germanium, and gallium arsenide. Of the three, germanium was one of the earliest semiconductor materials used. Germanium has four valence electrons, which are electrons located on the outer shell of the atom.

What metals are in semiconductors?

What are ohmic and Schottky contacts?

An ohmic contact is a non-rectifying electrical junction: a junction between two conductors that has a linear current–voltage (I-V) curve as with Ohm’s law. Non-ohmic contacts come in a number of forms, such as p–n junction, Schottky barrier, rectifying heterojunction, or breakdown junction.

What is the difference between ohmic contact and Schottky contact?

Schottky Contacts make good diodes, and can even be used to make a kind of transistor, but for getting signals into and out of a semiconductor device, we generally want a contact that is Ohmic. Ohmic contacts conduct the same for both polarities. (They obey Ohm’s Law).

What do you mean contact resistance?

Contact resistance is the resistance to current flow, due to surface conditions and other causes, when contacts are touching one another (in the closed condition of the device).

What is difference between ohmic contact and Schottky contact?

Why are metal semiconductor contacts annealed or alloyed?

Most metal-semiconductor contacts are annealed or alloyed after the initial deposition of the metal in an effort to further improve the contact resistivity. This section describes each of these contacts as well as an analysis of the contact resistance between a metal and a thin semiconductor layer.

What is a metal-semiconductor junction?

A metal-semiconductor junction results in an Ohmic contact (i.e. a contact with voltage independent resistance) if the Schottky barrier height, fB, is zero or negative. In such case, the carriers are free to flow in or out of the semiconductor so that there is a minimal resistance across the contact.

What factors affect contact formation in semiconductor materials?

Thin interfacial layers also affect contact formation. Most metal-semiconductor contacts are annealed or alloyed after the initial deposition of the metal in an effort to further improve the contact resistivity.

How do you make a tunnel contact between semiconductors?

However for a lot of semiconductors there is no appropriate metal available. Instead one then creates a tunnel contact. Such contact consists of a thin barrier – obtained by heavily-doping the semiconductor – through which carriers can readily tunnel.