In photonic integrated circuits (PICs) having at least one active semiconductor
device, such as, a buried heterostructure semiconductor laser, LED, modulator,
photodiode, heterojunction bipolar transistor, field effect transistor or other
active device, a plurality of semiconductor layers are formed on a substrate with
one of the layers being an active region. A current channel is formed through this
active region defined by current blocking layers formed on adjacent sides of a
designated active region channel where the blocking layers substantially confine
the current through the channel. The blocking layers are characterized by being
an aluminum-containing Group III-V compound, i.e., an Al-III-V layer, intentionally
doped with oxygen from an oxide source. Also, wet oxide process or a deposited
oxide source may be used to laterally form a native oxide of the Al-III-V layer.
An example of a material system for this invention useful at optical telecommunication
wavelengths is InGaAsP/InP where the Al-III-V layer comprises InAlAs:O or InAlAs:O:Fe.
Other materials for the blocking layers may be InAlGaAs or alternating layers or
alternating monolayers of AlAs/InAs. Thus, the O-doped blocking layers may be undoped,
impurity doped or co-doped with Fe.
