(IV).sub.x (III-V).sub.1-x alloys formed in situ in III-V heterostructures

摘要

A high performance III-V heterostructures exhibiting quantum size effects has been achieved in MODCVD utilizing in situ grown (IV).sub. x (III-V).sub.1-x alloys, where (IV) is a group IV element comprising Si, Ge, C or Sn or admixtures thereof and (III-V) is a group III-V binary, trinary, quaternary or pentad compound or alloy such as, for example, GaAs, AlAs, GaAlAs, GaAlAsP, InGaAlP, InAlAsP or InGaAlAsP. Specific examples are (Si.sub.2).sub.x (GaAs).sub.1-x, which is an alloy that functions as a barrier when grown in situ in a GaAs active region of a heterostructure and (Ge.sub.2).sub.x (GaAs).sub.1-x, which is an alloy that functions as a quantum well when grown in situ in GaAs or GaAlAs active region (e.g. highest refractive index and narrowest bandgap) of a heterostructure. The disclosure further relates to the utilization of a nucleating or catalytic process wherein a small amount of a cluster collector or anchorage component, e.g., Al, Mg or Ti, on the surface of the sample in the reaction zone of the MOCVD reactor. This component is believed to function as a nucleating or catalytic site to which IV--IV pairs initially attach and, thereafter, continually attach to form islands that provide three dimensional barriers or wells in an active region of a heterostructure. Another aspect of the disclosure deals with in situ induced disordering vis a vis surface initiated impurity induced disordering (SIIID) as known in the art. Superlattice or well disordering can be achieved in situ during crystal growth rather than by introduction of an impurity component into the superlattice as contemplated in SIIID.