The unique electronic, physical, optical, and thermal properties of WBG semiconductors, including diamond, make these materials among the most prospective for high-frequency power electronics, quantum computing, solar-blind radiation detectors, and bio-medical applications.

Following NIST's mission to promote U.S. innovation and industrial competitiveness by advancing US measurement science, standards, and technology, the Advanced Electronics group of Physical Measurements Laboratory recently initiated research in the field of WBG. In particular, in our lab, we have dedicated instrumentation to fabricate and characterize complex semiconductor interfaces using microscopy (SEM, EBIC, STM) and spectroscopy (XPS, AES, EDX, μ-Raman, cathodoluminescence) methods combined with in situ electrical measurements. The lab has advanced sample preparation equipment (including cross-sections) and also an ability to fabricate prototype devices using electron lithography.

The current topics of interest include the process development and optimization for large-scale fabrication of diamond-based devices such as HMFETs and radiation detectors. In particular, the transfer doping of hydrogenated diamond is used to form 2D hole gas (2DHG) conducting channel in diamond FET. The hole transport in such a device sensitively depends on the semiconductor-gate insulator interface and subsurface scatterers including charged traps. The effort is to optimize the materials and processing at interfaces to improve the diamond HMFET parameters and device fabrication scalability.

Relevant references:

1.       Sasama, Yosuke, et al. "High-mobility p-channel wide-bandgap transistors based on hydrogen-terminated diamond/hexagonal boron nitride heterostructures." Nature Electronics 5.1 (2022): 37-44.

2.       Jingu, Yoshikatsu, Kazuyuki Hirama, and Hiroshi Kawarada. "Ultrashallow TiC source/drain contacts in diamond MOSFETs formed by hydrogenation-last approach." IEEE transactions on electron devices 57.5 (2010): 966-972.

3.       Neupane, Mahesh, et al. "Novel acceptor layer technology for diamond electronics." Radar Sensor Technology XXV. Vol. 11742. SPIE, 2021.