The Influence of Process Parameters on Hydrogen-Terminated Diamond and the Enhancement of Carrier Mobility

With the development of diamond technology, its application in the field of electronics has become a new research hotspot. Hydrogen-terminated diamond has the electrical properties of P-type conduction due to the formation of two-dimensional hole gas (2DHG) on its surface. However, due to various scattering mechanisms on the surface, its carrier mobility is limited to 50-200 cm²/(Vs). In this paper, the effects of process parameters (temperature, CH₄ concentration, time) on the electrical properties of hydrogen-terminated diamond were studied by microwave plasma chemical vapor deposition (CVD) technology, and hydrogen-terminated diamond with a high carrier mobility was obtained. The results show that homoepitaxial growth of a diamond film on a diamond substrate can improve the carrier mobility. Hydrogen-terminated diamond with a high carrier mobility and low sheet resistance can be obtained by homoepitaxial growth of a high-quality diamond film on a diamond substrate with 4% CH₄ concentration and hydrogen plasma treatment at 900 ℃ for 30 min. When the carrier concentration is 2.03 × 10¹²/cm², the carrier mobility is 395 cm²/(Vs), and the sheet resistance is 7.82 kΩ/square, which greatly improves the electrical properties of hydrogen-terminated diamond. It can enhance the transmission characteristics of carriers in the conductive channel, and is expected to become a potential material for application in devices, providing a material choice for its application in the field of semiconductor devices.