I agree with the other responses. I'll add that the word epitaxy indicates the objective of crystal growth versus simple deposition. The goal is to maintain the underlying crystal structure of the substrate and have it continue through the various MBE grown layers even as the material layers change. Thus, the various layers of material must have the same crystalline structure and similar lattice constant as the underlying substrate. If two layers with a large difference in lattice constant are desired, then transition layers might be used. The advantages of MBE include the crystal purity and ability to control film thickness to the monolayer. MBE layers can be made so thin that quantum mechanical effects can be engineered into a material. Since the crystal structure must closely match, there is a fundamental limitation to the available materials for a given substrate or material system. MBE is also slow, so it requires an ultra-high vacuum environment.

Sputtering involves dislodging material from a sputtering target using a high-energy source beam. The sputtered material (typically atoms and ions) deposit onto a substrate. The goal is a homogeneous film. Sputtering is not epitaxial - there is no attempt at maintaining the crystalline structure of the film or matching it with the substrate. The film is deposited not grown. For this reason, there are fewer fundamental limitations on the type of materials that can be sputtered on a given substrate. Sputtering is also faster than MBE, so it does not require the same high vacuum levels. Since the films a largely amorphous, sputtering offers the advantage of tailoring the density by changing the deposition parameters. The refractive index of a sputtered film, for example, may be tailored. Sputtering is also capable of creating very dense films compared with other thin film deposition techniques.

Dear Singh,

MBE is an atomic layer by atomic layer deposition technique, which is based on reaction of molecular or atomic beams on the heated substrate in an ultra-high vacuum (UHV) environment. The term “molecular beam” depicts a unidirectional kinematic flow of atoms or molecules without collisions. Here the deposited species may be atomic or molecules because its matter of chance phenomena. Since, atom is the part of molecule that why called MBE.

In MBE, the absence of carrier gases, as well as the ultra-high vacuum environment, result in the highest achievable purity of the grown films. It is also used for the deposition of some types of organic semiconductors. But sputtering is a atom by atom deposition technique. Here, we need to create a reactive environment in high vacuum not ultrahigh. Quality may be an issue in sputtering in comparison of MBE.

For example, MBE with Mercury delivers Mercury atoms to the surface, but Arsenic can arrive as As4 molecules.

A big difference between sputtering and MBE is that MBE will give you a high quality crystal, while sputtering normally gives an amorphous (or at best polycrystaline) layer.

Dear Singh,

Better purity of materials are obtained for MBE while in Sputtering the possibility of incorporating impurity is great. On another hand, it is generally assumed that sputtered films adhere better than evaporated films but stresses can be higher. Also, change in source material is very easy in MBE technique and very expensive in sputtering.

Best regards

Yes MBE is precise atomic layer by layer growth technique where substrate is in UHV but sputter is forced deposition in vacuum chamber normally growth in poly or amorphous type.

I agree with the other responses. I'll add that the word epitaxy indicates the objective of crystal growth versus simple deposition. The goal is to maintain the underlying crystal structure of the substrate and have it continue through the various MBE grown layers even as the material layers change. Thus, the various layers of material must have the same crystalline structure and similar lattice constant as the underlying substrate. If two layers with a large difference in lattice constant are desired, then transition layers might be used. The advantages of MBE include the crystal purity and ability to control film thickness to the monolayer. MBE layers can be made so thin that quantum mechanical effects can be engineered into a material. Since the crystal structure must closely match, there is a fundamental limitation to the available materials for a given substrate or material system. MBE is also slow, so it requires an ultra-high vacuum environment.

Sputtering involves dislodging material from a sputtering target using a high-energy source beam. The sputtered material (typically atoms and ions) deposit onto a substrate. The goal is a homogeneous film. Sputtering is not epitaxial - there is no attempt at maintaining the crystalline structure of the film or matching it with the substrate. The film is deposited not grown. For this reason, there are fewer fundamental limitations on the type of materials that can be sputtered on a given substrate. Sputtering is also faster than MBE, so it does not require the same high vacuum levels. Since the films a largely amorphous, sputtering offers the advantage of tailoring the density by changing the deposition parameters. The refractive index of a sputtered film, for example, may be tailored. Sputtering is also capable of creating very dense films compared with other thin film deposition techniques.

Fully agree with previous answers.

I should add that there is MOCVD technique which differs from MBE and sputtering.

MOCVD works under at moderate gas pressures, it provides a better film quality than traditional sputtering methods and it is faster than MBE.

MBE is thought as a thin epitaxial layer forming method by physical methods where the material is evaporated and made in a form of beams which is made to deposit epitaxially on a heated substrate. One wants to build thin epitaxial layers at relatively low temperature compared to the epitaxial growth by means of chemical vapor deposition. In fact it is a method to build epitaxial films atomic layer by atomic layer on relatively low temperature substrate. This helps build epitaxial layers with abrupt doping profiles.

Sputtering is used to deposit sputtered material dust on the cathode of the sputtering machine. Normally the substrate is kept at low temperature and so the deposited layer will be amorphous, which makes a very great difference with the MBE. Better than MBE is the MOCVD as it allows epitaxial growth with higher rate at relatively low temperature. It is not need ultra high vacuum as the MBE.

Best wishes

Read the work by

Sun group

from

Norteastern Universiy