The problem of manufacturing high purity semiconductor materials with super high electron mobility is among important, though technologically difficult ones.

Traditional with regard to III-V compounds this problem has been solved using the following technique

- the choice of alternative crucible material

- the application of high purity initial materials

- oxygen doping for shallow donors removal

- isoelectronic doping (e.g. bismuth)

We can also mention other attractive directions in this sphere of activity, such as secondary methods of influence upon the crystals grown - heat treatment and purification by radiation methods, the latter ones still wanting being explored.

From the late 70's we have been carrying out the investigations of the rare-earths (RE) influence upon the electrical characteristics of InP, and later - of GaAs.

In this work submitted are the results of comprehensive investigation of RE applications in bulk III-V crystal growth technology with the aim of purification and heavy doping of the crystals.