Band lineup for a GaInP/GaAs heterojunction measured by a high‐gainNpnheterojunction bipolar transistor grown by metalorganic chemical vapor deposition

摘要

A GaInP(N)/GaAs( p) heterojunction bipolar transistor was fabricated by metalorganic chemical vapor deposition (MOCVD) for the first time. The common‐emitter current gain exceeded 200 at a current density around 10 A/cm2and the offset voltage was as small as 50 mV. Thermionic emission theory indicates that the conduction‐band discontinuity (Dgr;Ec) at GaInP/GaAs heterointerface is as small as 30 meV at room temperature and this value was more than 160 meV smaller than 0.19–0.22 eV obtained by theC‐Vprofile method. The band‐gap energy for MOCVD‐grown GaInP was 60 meV smaller than the intrinsic band‐gap energy (1.91 eV), but this value is too small to explain the difference between the present Dgr;Ecvalue and the previously reported Dgr;Ecvalue.