High-pressure Liquid Encapsulated Czochralski Research Articles

Undoped semi-insulating LEC GaAs: a model and a mechanism

Undoped semi-insulating GaAs grown by the high-pressure liquid encapsulated Czochralski (LEC) method has been produced for use in direct ion implantation in several laboratories. A clear understanding of the factors controlling impurity transport and compensation in these materials has been lacking to date. In this work, detailed characterization has been performed on undoped semi-insulating crystals grown from both SiO2 and PBN crucibles followed by a proposed impurity model and compensation mechanism.

Preparation and crystal growth of NiS(h)

A procedure is described for the preparation of 90 g batches of NiS. Molten NiS has been shown to exert a pressure of about 9 atm of sulphur and to be compatible with liquid B2O3. Near single crystals of NiS(h) have been grown by the high pressure liquid encapsulated Czochralski technique. Evidence suggests that the as-grown crystals exhibit variable stoichiometry and an annealing procedure which gives apparently homogeneous samples is described.