An Overview of High-k Oxides on Hydrogenated-Diamond for Metal-Oxide-Semiconductor Capacitors and Field-Effect Transistors

Thanks to its excellent intrinsic properties, diamond is promising for applications of high-power electronic devices, ultraviolet detectors, biosensors, high-temperature tolerant gas sensors, etc. Here, an overview of high-k oxides on hydrogenated-diamond (H-diamond) for metal-oxide-semiconductor (MOS) capacitors and MOS field-effect transistors (MOSFETs) is demonstrated. Fabrication routines for the H-diamond MOS capacitors and MOSFETs, band configurations of oxide/H-diamond heterointerfaces, and electrical properties of the MOS and MOSFETs are summarized and discussed. High-k oxide insulators are deposited using atomic layer deposition (ALD) and sputtering deposition (SD) techniques. Electrical properties of the H-diamond MOS capacitors with high-k oxides of ALD-Al(2)O(3), ALD-HfO(2), ALD-HfO(2)/ALD-Al(2)O(3) multilayer, SD-HfO(2)/ALD-HfO(2) bilayer, SD-TiO(2)/ALD-Al(2)O(3) bilayer, and ALD-TiO(2)/ALD-Al(2)O(3) bilayer are discussed. Analyses for capacitance-voltage characteristics of them show that there are low fixed and trapped charge densities for the ALD-Al(2)O(3)/H-diamond and SD-HfO(2)/ALD-HfO(2)/H-diamond MOS capacitors. The k value of 27.2 for the ALD-TiO(2)/ALD-Al(2)O(3) bilayer is larger than those of the other oxide insulators. Drain-source current versus voltage curves show distinct pitch-off and p-type channel characteristics for the ALD-Al(2)O(3)/H-diamond, SD-HfO(2)/ALD-HfO(2)/H-diamond, and ALD-TiO(2)/ALD-Al(2)O(3)/H-diamond MOSFETs. Understanding of fabrication routines and electrical properties for the high-k oxide/H-diamond MOS electronic devices is meaningful for the fabrication of high-performance H-diamond MOS capacitor and MOSFET gas sensors.