Fabrication of InP/InGaAs SHBT on Si Substrate by Using Transferred Substrate Process

Abstract

With the aim of achieving heterogeneous integration of compound semiconductors with silicon technology, the fabrication of an InP/InGaAs transferred-substrate HBT (TS-HBT) on a Si substrate is reported. A current gain of 70 and a maximum current density of 12.3mA/µm² were confirmed in a TS-HBT with a 340-nm-wide emitter. From microwave characteristics of the TS-HBT obtained after de-embedding, a cutoff frequency (f_T) of 510GHz and a 26% reduction of the base-collector capacitance were estimated. However, the observed f_T was too high for an HBT with a 150-nm-thick collector. This discrepancy can be explained by the error in de-embedding, because an open pad is observed to have large capacitance and strong frequency dependence due to the conductivity of the Si substrate.