Method for successfully depositing doped II-VI epitaxial layers by organometallic chemical vapor deposition

Claim 1

A method of depositing a doped epitaxial layer of a II-VI compound on the surface of a substrate in a deposition zone of a reactor of an organometallic chemical vapor deposition system comprising the steps of heating the deposition zone of the reactor to a temperature in the range of about 300° C. to 400° C. to produce pyrolytic action that provides sufficient surface mobility of the compound to be deposited to form a smooth epitaxially deposited layer, the temperature employed in said range being not so high as to produce a substantial concentration of native intrinsic defects, said defects being comparatively smaller in number relative to the number of electrically active doners therein, introducing into the reactor a gas phase composition containing a gaseous mixture of a reactant having a Group II containing component, a reactant having a Group VI containing component and a dopant selected from the Group III for n-type dopant or from the Group V for the p-type dopant, said step of introducing characterized by one of the gas phase reactants thereof and said selected dopant being initially introduced in close proximity to the substrate surface in the deposition zone whereas other gas phase reactants are introduced directly into the reactor proper. selecting a low pressure environment in the range of about 10 mTorr to 200 mTorr in the reactor, said selection sufficient to suppress the probability of the gas phase pyrolytic reaction of said mixture prior to deposition thereof on the substrate. forming said epitaxial layer by contacting the substrate with the introduced mixture in the deposition zone causing the pyrolyzation and deposition on the substrate of an elemental II and VI compound with a predetermined doping concentration.

Claim 2

A method of depositing a doped epitaxial layer of a II-VI compound on the surface of a substrate in a deposition zone of a reactor of an organometallic chemical vapor deposition system comprising the steps of heating the deposition zone of the reactor to a temperature in the range of about 300° C. to 400° C. to produce pyrolytic action that provides sufficient surface mobility of the compound to be deposited to form a smooth epitaxially deposited layer, the temperature employed in said range being not so high as to produce a substantial concentration of native intrinsic defects, said defects being comparatively smaller in number relative to the number of electrically active doners therein, introducing into the reactor a gas phase composition containing a gaseous mixture of a reactant having a Group II containing component, a reactant having a Group VI containing component and a dopant selected from the Group III for n-type dopant or from the Group V for the p-type dopant, said step of introducing characterized by one of the gas phase reactants thereof and said selected dopant being initially introduced in close proximity to the substrate surface in the deposition zone whereas other gas phase reactants are introduced directly into the reactor proper. selecting a low pressure environment in the range of about 10 mTorr to 200 mTorr in the reactor, said selection sufficient to suppress the probability of the gas phase pyrolytic reaction of said mixture prior to deposition thereof on the substrate. forming said epitaxial layer by contacting the substrate with the introduced mixture in the deposition zone causing the pyrolyzation and deposition on the substrate of an elemental II and VI compound with a predetermined doping concentration.