Inverted Fin 2-D Material U-shaped Transistor
Publication Date: 2015-May-07
The IP.com Prior Art Database
Disclosed is a design for an inverted fin with a U-shaped two-dimensional (2D) material such as Molybdenum disulfide (MoS2). MoS2 can be grown using chemical vapor deposition (CVD) on any surface, which enables the formation of fins in the trenches, and then Chemical Mechanical Planarization (CMP).
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Inverted Fin 2
Two-dimensional (2D) materials are touted for ultimate Complimentary Metal -Oxide Semiconductors (CMOS). While Graphene has small or negative bandgap , Molybdenum disulfide (MoS2) offers considerable bandgap and allows low-leakage CMOS operation. Three-dimensional (3D) structures using 2D materials are required to increase current density per footprint. Prior art focuses on 3D dual channel 2D/fin or nanowire structure, which has the problem of dual channel conduction , which may not be favorable for device design.
The novel contribution is a design for an inverted fin with a U -shaped 2D material such as MoS2. Unlike Germanium/Silicon (Ge/Si), which grows only epitaxially, MoS2 can be grown using chemical vapor deposition (CVD) on any surface, such as dielectrics. Thus, fins can be formed in the trenches and Chemical -Mechanical Planarized (CMP'ed). The fin height can be adjusted by the dielectric thickness . The contact can be made in the trench with enough area and has potential to offer improved contact resistivity.
Following are the steps for implementing the design for an inverted fin with a U -shaped 2D material in a preferred embodiment.
Step #1: Deposit a dielectric stack (e.g., nitride plus oxide) onto a silicon substrate. The bottom dielectric serves as the etch stop and can be 10nm-30nm in thickness. The top dielectric thickness is equal to the depth of the trench , which eventually forms to create the U-shaped transistor.
Step #2: Patt...