Investigation of Ge-Based P-Channel Planar-Doped Barrier FETs integrated on Si

Abstract

Ge-based p-channel Field-Effect Transistors (FETs) are regarded as the most promising devices to replace Si-based p-channel FETs with emphasis on reducing device power-consumption. Planar-Doped Barrier FETs (PDBFETs) are considered good candidates for tuning Ge-based FETs performance: with channels almost undoped except for a very thin region, creating necessary barrier for operation. PDBFETs enables inspection of behaviour with carriers away from surface, experiencing bulk properties. The aim of this work is to show the capability of the PDBFET concept to improve the performance of Ge-based devices even on large scaled device. Applying the concept of channel doping modulation to Ge-based FETs is demonstrated through fabrication and electrical characterization of Ge-based p-PDBFETs with optimistic results achieving off-state currents of sub-nA/μm even with relatively large sized devices, which are competitive in electrostatic performance to scaled, more complicated design devices. Sources of leakage current are considered through improving surface treatment. Applying low temperature measurements elaborated the possibility of higher performance with dimension scaling availability.