SiGeHBTs on bonded wafer substrates

Silicon germanium (SiGe) heterojunction transistors have been fabricated on bonded wafer, silicon-on-insulator (SOI) substrates. The devices have appl ication in low power, radio-frequency electronics. The bonded wafer substra tes incorporate poly-Si filled, deep trenches for isolation. A novel select ive and non-selective low pressure chemical vapour deposition (LPCVD) growt h process was used for the epitaxial layers. Experimental transistors exhib it good uniformity across the wafers and collector currents are seen to be ideal, showing the expected enhancement for the SiGe devices compared to Si . Anomalies in device characteristics at high current levels are investigat ed. (C) 2001 Elsevier Science B.V. All rights reserved.