High-speed InAIAs/InGaAs HBTs on 4-inch S.I. GaAs substrates

In this paper, we describe high-speed InAlAs/InGaAs HBTs on 4-inch S.I. GaAs substrates, which were made with constitutionally graded lattice-buffer layers and optimization of the epitaxial growth temperature. The use of these structures leads to excellent RF characteristics in spite of the thick base (200 nm) and collector (600 nm) of the HBTs. The maximum frequency (fmax) and the current gain cut-off frequency (ft) are 53 GHz and 37 GHz, respectively. We achieved a delay time of 26 ps for an ECL gate, which consists of 130 transistors, 150 resistors, and 10 capacitors on a 4-inch GaAs substrate