InP Crystal Phase Heterojunction Transistor with a Vertical Gate-All-Around Structure

Area of Science:

• Materials Science
• Condensed Matter Physics
• Semiconductor Device Physics

Background:

• Crystal phase heterojunctions (CPHJs) are formed by different atomic arrangements within the same material.
• CPHJs offer unique band engineering possibilities without critical thickness or misfit dislocation issues.
• Previous CPHJ applications in 2D transition-metal dichalcogenides faced scalability limitations.

Purpose of the Study:

• To demonstrate a transistor utilizing CPHJ in conventional III-V semiconductors with a vertical gate-all-around structure.
• To overcome the geometrical limitations of in-plane CPHJ devices for improved scalability.
• To explore a new switching mechanism and device design for transistors.

Main Methods:

• Fabrication of a CPHJ using wurtzite InP nanowires on zincblende InP substrates.
• Characterization of the heterojunction's atomic structure and band alignment.
• Electrical testing of the CPHJ transistor performance, including gate controllability and current characteristics.

Main Results:

• An atomically flat CPHJ was successfully formed without dislocations.
• A Type-II band discontinuity was observed across the wurtzite/zincblende InP heterojunction.
• The CPHJ transistor exhibited moderate to good gate electrostatic controllability, high on-state currents, and high transconductance.

Conclusions:

• CPHJs in III-V semiconductors enable vertical transistors with enhanced performance.
• This approach provides a scalable alternative to 2D CPHJ devices.
• CPHJs represent a significant advancement in transistor design and switching mechanisms.