Bulk Barrier Source-Gated Transistors with Improved Drain Current Dynamic Range and Temperature Coefficient

Abstract

Source-gated thin-film transistors (SGTs) have remarkable properties related to low-voltage amplification, tolerance to process variation and electrical stability. They rely on a potential barrier at the source in their operation, and usually this barrier is realized through a Schottky contact. Here, we study SGTs with source barriers made by doping the source region of the semiconductor to form bulk unipolar diodes (BUD). A BUSGT can have much higher drain current with a lower activation energy, resulting in higher switching speed and improved transconductance. Barriers made via doping also provide a wider range of barrier heights compared with Schottky contacts. We discuss design parameters for BUSGTs and compare these devices with SBSGTs.

Novel Tunnel‐Contact‐Controlled IGZO Thin‐Film Transistors with High Tolerance to Geometrical Variability

“…Consequently, the injection of charge from the bulk of the source electrode is by processes which result in low activation energy and high intrinsic gain . The barrier at the source of an SGT device is typically realized by a Schottky contact, but it is also possible to realize a similar effect by other means …”

“…To put the characteristics of the proposed devices in context, we refer to Table 1 , which synthesizes the structural differences and their impact on electrical behavior for contact‐controlled devices with: Schottky barriers (traditional SGT), bulk or heterostructure barriers, and the proposed tunnel barriers. Choosing the most suitable design will depend in equal measure on the application and on the practicalities of fabrication (e.g., ability to produce reliable nanoscale contact barrier layers on a large area for the tunnel devices, or solvent orthogonality for solution‐processed heterojunction‐barrier devices).…”