MOCVD growth of InGaP/GaAs heterojunction bipolar transistors on 200 mm Si wafers for heterogeneous integration with Si CMOS

Heterojunction bipolar transistors (HBTs) with an In_0.49Ga_0.51P emitter and a GaAs base and collector were fabricated on epitaxial films grown directly onto Si substrates using a thin germanium (100%) buffer layer. All the materials (Ge, GaAs, In_0.49Ga_0.51P) were grown epitaxially using metal–organic chemical vapor deposition. The thin germanium buffer layer has a threading dislocation density (TDD) of ∼3 × 10⁷ cm⁻². The TDD of the active device layers does not worsen and is maintained at ∼2 × 10⁷ cm⁻², based on the density of dark spots detected in an electron-beam-induced current plan view image. Although the TDD is high, a DC current gain of 95 can be achieved by the In_0.49Ga_0.51P/GaAs HBT on a Si substrate. In addition, collector current and base current ideality factors (n _c and n _b) of 1.07 and 1.23, respectively, and average breakdown voltage (BV _cbo) of 14.2 V can be realized. These results enable applications such as power amplifiers for mobile phone handsets and monolithic integration of HBTs with standard Si CMOS transistors on a common Si platform. (paper)