III-Nitride Vertical Hot-Electron Transistor with Polarization Doping and Collimated Injection

III-nitride-based technologies are pivotal in advancing high-speed and high-power electronic devices essential for applications such as telecommunications, power electronics, and high-frequency signal processing. The inherent properties of III-nitrides, including wide bandgaps, high electron mobility, and thermal stability, make them ideal candidates for developing transistors that can operate efficiently under demanding conditions. As industries push for faster and more reliable electronic components, the demand grows for sophisticated transistor technologies that can deliver superior performance while managing power effectively. However, current approaches to III-nitride transistor design face significant challenges to their performance. Traditional hot-electron transistors (HETs) in this field have struggled to achieve collector current densities and current gains that compete with alternative technologies. Issues such as excessive electron scattering in the base region, high turn-on voltages, and elevated base access resistance limit the overall efficiency and scalability of these devices. Additionally, conventional fabrication techniques often result in structural damages and suboptimal layer interfaces, further compromising device performance. These limitations underscore the need for innovative engineering and fabrication strategies to unlock the full potential of III-nitride-based transistors.

Technology Description

The III-nitride vertical hot-electron transistor (HET) exhibits exceptional performance with a collector current density surpassing 440 kA/cm² and a common-emitter current gain exceeding 75. This high-performance device is achieved through a polarization-engineered emitter stack that enables focused, high-current electron injection with a relatively low turn-on voltage. The structure includes a precisely layered architecture comprising highly doped and graded AlGaN layers, an AlN tunneling barrier, and an undoped 10 nm-thick GaN base that maintains a high electron gas density while minimizing scattering. Advanced fabrication techniques, such as BCl₃/O₂ atomic layer etching, ensure low-damage contacts and reduced base access resistance, enhancing overall device efficiency and reliability.

What sets this HET apart is its innovative use of polarization engineering and meticulous layer design, which create a triangular quantum well adjacent to the AlN tunneling barrier. This configuration allows for thermionically filled, collimated electron injection that is high in current and highly directed, significantly reducing electron scattering in the undoped base. Additionally, the implementation of atomic layer etching for contact formation minimizes structural damage and access resistance, ensuring optimal electrical performance. These distinctive features collectively enable the HET to outperform competing technologies, offering a unique combination of high speed, power, and gain that distinguishes it in the field of high-performance electronic devices.