Demonstration of Symmetric Lateral NPN Transistors on SOI Featuring Epitaxially Grown Emitter/Collector Regions

Symmetric lateral NPN bipolar junction transistors on Si-on-insulator having epitaxially grown emitter/collector regions are demonstrated, for the first time. A novel notch-assisted epitaxy scheme has been developed using faceted Si epitaxial (epi) layers as reactive-ion-etch mask to expose the vertical intrinsic-base epi-seeding surfaces and the epi emitter and collector are automatically connected to the extension regions for metal contact and/or for electrical probing. Functional transistors with good quality device I-V characteristics were obtained with post-epi rapid thermal annealing. The results suggest a path forward for devices suitable for low-cost THz electronics applications. Some learning about the fabrication, as revealed from measured device characteristics, are discussed.