P-n junction devices with group iv element-doped group iii-v compound

Abstract

This invention embodies p-n junction devices comprising Group III-V compound semiconductors in which the p or n or both p and n regions are formed by a superlattice selectively doped with an amphoteric Group IV element dopant selected from carbon, germanium and silicone. The superlattice includes a plurality of periods, each including two layers. Depending on the conductivity type, only one of the layers in the periods forming the superlattice region of said type of conductivity is selectively doped with said dopant, leaving the other layer in these periods undoped. The superlattice is formed by Molecular Beam Epitaxy technique, and the dopant is incorporated into respective layers by delta-doping as in a sheet centrally deposited between monolayers forming the respective layers of the period. Each period includes 5 to 15 monolayers deposited in the two layers in a numerical ratio corresponding to a cation compositional ratio in the compound semiconductor. Low growth temperatures, e.g. ranging from 410.degree. to 450.degree. C. lead to mirror-like surfaces. For a compound semiconductor Ga.sub.0.47 In.sub.0.53 As, the GaAs/InAs ordered superlattices with eight monolayers per period are grown in a ratio of 0.47/0.53. At free carrier concentrations of 10.sup.16 cm.sup. -3, carrier mobilities of 200 and 2300 cm.sup.2 /Vs for p-type and n-type are obtained with carbon as the amphoteric dopant.