Crystal growth

Question 1

What is the name of the method for producing a crystalline semiconductor?

Answer 1

Czochralski method

Question 2

What are the steps for the Czochralski method?

Answer 2

Purify a compound of silica, producing a melt

The melt is put around a small seed crystal

The melt and crystal are pulled up, and cool down

As they cool down, the melt and crystal crystallise

The structure is based on the seed crystal

Question 3

What is epitaxy?

Answer 3

growing a crystalline thin form on a crystalline substrate

Question 4

What are the names of the methods for epitaxy?

Answer 4

Metal-organic chemical vapour deposition (MOCVD) and Atomic Layer Deposition

Question 5

What are the steps for MOCVD?

Answer 5

Precursor materials are entered into a reaction chamber

The reaction chamber has a substrate at a very high temperature

The temperature manages to decompose the precursors

This leaves only the desired elements on the surface, resulting in crystal growth

Question 6

What does Atomic Layer Deposition aim to achieve?

Answer 6

a layer of zinc sulphide

Question 7

What are the steps for Atomic Layer Deposition?

Answer 7

Zinc chloride molecules form a singular layer on the surface

Once the layer is formed the reaction stops [so any other molecules will not react, and excess molecules will be purged]

Hydrogen sulphide then reacts with ZnCl, forming a layer of ZnS