Compact Model Predicts Mobile Charge Density in Polar Multiple-Channel III-Nitride Field Effect Transistors

The design of high-performance transistors increasingly relies on complex semiconductor structures, and accurately modelling charge behaviour within these devices presents a significant challenge. Aias Asteris, Thai-Son Nguyen, Huili G. Xing, and Debdeep Jena from Cornell University have developed a new compact model to predict mobile charge density in polar multiple-channel field-effect transistors, a technology promising for advanced electronics. This model leverages fundamental principles of electrostatics and mechanics to estimate electron and hole populations within multi-layered structures, specifically focusing on III-Nitride semiconductors like AlGaN/GaN, AlInN/GaN, and AlScN/GaN. By accurately capturing the effects of spontaneous and piezoelectric polarization, and incorporating techniques to control hole gas depletion through doping, the team’s work substantially simplifies and accelerates the design process for these complex, multi-layered transistors, paving the way for more efficient and powerful electronic devices.

GaN Heterostructure Modeling for Device Performance

Scientists have developed a compact analytical model to precisely estimate mobile charge density within polar multiple channel field effect transistors, devices that utilize the unique properties of layered materials. By applying fundamental electrostatic and mechanical principles, the team estimated total electron and hole populations within the active regions of these transistors, culminating in a generalized equation that accurately predicts mobile carrier density across various doping schemes.

Mobile Carrier Density in Polar Transistors

Scientists have developed a compact analytical model to accurately estimate mobile carrier density within polar multiple channel field effect transistors, crucial devices for advanced electronics and photonics. This work focuses on heterostructures, layered materials comprising III-Nitride semiconductors, and establishes a fundamental understanding of how electron and hole gases behave within these complex structures. The team successfully derived a generalized equation that predicts mobile carrier density across various doping schemes, accounting for the depletion and enhancement of these gases through intentional material modification. Experiments demonstrated the model’s utility by correlating barrier thickness with two-dimensional electron gas (2DEG) formation, revealing that the critical barrier thickness for 2DEG onset is lowest for AlScN, increasing for AlInN, and highest for AlGaN.

Measurements confirm strong agreement between the analytical model and self-consistent numerical calculations, with minor discrepancies at high 2DEG densities due to single subband occupancy consideration. As barrier thickness increases, the expected 2DEG density also increases, with larger polarization discontinuities inducing higher densities. Extending this work to multi-channel transistors, scientists assumed that outermost 2DEGs electrically isolate inner channels, simplifying the analysis. The team derived a closed-form equation for 2DEG/2DHG density within periodic channels subject to periodic boundary conditions, and adapted this equation to model the top and bottom channels, revealing that 2DEG formation is always accompanied by an adjacent 2DHG of equal density. This detailed model provides a powerful tool for designing and optimizing multi-channel field effect transistors, paving the way for improved device performance and functionality.

Carrier Density Prediction in III-Nitride Heterostructures

Scientists have developed a compact analytical model to accurately estimate mobile carrier density within polar multiple channel field effect transistors, crucial devices for advanced electronics and photonics. This work focuses on heterostructures, layered materials comprising III-Nitride semiconductors, and establishes a fundamental understanding of how electron and hole gases behave within these complex structures. The team successfully derived a generalized equation that predicts mobile carrier density across various doping schemes, accounting for the depletion and enhancement of these gases through intentional material modification. This model significantly improves the efficiency of multilayered transistor design by providing a transparent and accurate method for determining carrier gas densities.

The researchers demonstrated the model’s utility using several III-Nitride material combinations, revealing how doping affects electric field strength and carrier mobility. While acknowledging that remote Coulomb scattering can impact carrier mobility, the model provides a framework for carefully engineering doping to optimize device performance. This work establishes a foundation for future research, specifically the analysis of source, drain, and gate characteristics to complete a comprehensive compact model for these transistors, complementing existing numerical simulation techniques and offering an efficient path for experimental design and validation.