Hafnium transistor process design for neural interfacing

Area of Science:

• Materials Science
• Electrical Engineering
• Biomedical Engineering

Background:

• Metal Insulator Semiconductor (MIS) transistors are crucial for neural recording applications.
• Designing the threshold voltage (Vth) is critical for optimal transistor performance in these devices.
• Hafnium oxide (HfO) is a promising gate dielectric material for advanced semiconductor devices.

Purpose of the Study:

• To develop an efficient design methodology for threshold voltage (Vth) in hafnium oxide (HfO) based Metal Insulator Semiconductor (MIS) transistors for neural recording.
• To minimize simulation time using 1-D process simulations while ensuring accurate Vth.
• To characterize HfO films for key dielectric properties influencing Vth.

Main Methods:

• Utilized 1-D analytical equations for threshold voltage (Vth) and doping profile specifications.
• Employed 1-D Metal Insulator Semiconductor (MIS) Technical Computer Aided Design (TCAD) for process design.
• Verified the 1-D simulation results with 2-D process/electrical TCAD simulations.
• Grew and characterized hafnium oxide (HfO) films, measuring dielectric constant and fixed oxide charge at various annealing temperatures.

Main Results:

• A design methodology using 1-D simulations was established for precise threshold voltage (Vth) control in HfO-based MIS transistors.
• The 1-D approach significantly reduced simulation time compared to traditional methods.
• Characterization of HfO films provided essential data on dielectric constant and fixed oxide charge, validating their role in Vth design.
• 2-D TCAD simulations confirmed the accuracy of the 1-D design methodology.

Conclusions:

• The presented 1-D simulation methodology offers an efficient and accurate approach for designing the threshold voltage (Vth) of hafnium oxide (HfO) based transistors for neural recording.
• This method optimizes the design process by minimizing simulation time, making it suitable for rapid prototyping and development.
• Understanding the impact of HfO film properties, such as dielectric constant and fixed oxide charge, is vital for successful threshold voltage engineering.