High temperature (300 °C) ALD grown Al2O3 on hydrogen terminated diamond: Band offset and electrical properties of the MOSFETs

Abstract

Hydrogen-terminated diamond (H-diamond) metal-oxide-semiconductor field effect transistors (MOSFETs) were fabricated on a polycrystalline diamond substrate. The device has a gate length of 2 μm and uses Al2O3 grown by atomic layer deposition at 300 °C as a gate dielectric and passivation layer. The Al2O3/H-diamond interfacial band configuration was investigated by X-ray photoelectron spectroscopy, and a large valence band offset (3.28 eV) that is very suitable for p-channel H-diamond FETs was observed. Meanwhile, the measured O/Al ratio hints that there are Oi or VAl defects in the Al2O3 dielectric, which can work as an acceptorlike transfer doping material on a H-diamond surface. The device delivers the maximum saturation drain current of over 200 mA/mm, which is the highest for 2-μm H-diamond MOSFETs with the gate dielectric or passivation layer grown at 300 °C or higher temperature. The ultrahigh on/off ratio of 1010 and ultralow gate leakage current of below 10−12 A have been achieved. The high device performance is ascribed to the ultrahigh carrier density, good interface characteristics, and device processes. In addition, the transient drain current response of the device can follow the gate voltage switching on/off pulse at a frequency from 100 kHz to 1 MHz, which indicates the potential of the H-diamond FETs in power switch applications.

Structural and electronic properties of 2D (graphene, hBN)/H-terminated diamond (100) heterostructures

“…Motivated by these experiments, recent theoretical modeling based on the effective mass approach predicted that a thin layer of 2D layer as an interfacial capping layer can minimize the impact of interface roughness or even facilitate the charge transfer across the H-diamond/acceptor layer interface and improve the sheet hole concentration. 19,20 Despite proof of improved device performance, theoretical effort to study the structural and electronic properties of 2D/H-diamond heterostructures with an atomistic resolution, particularly with hBN as the 2D layer, is still lacking. Furthermore, a fundamental understanding of the structural alignment and charge transfer between the 2D layer and H-diamond is key to the successful integration of 2D layers in nextgeneration scalable SD-based diamond devices.…”

Defect spectroscopy on the dielectric material aluminum oxide

“…This corresponds to an energy of 1.2 eV below the conduction band of . Taking an offset of 3.6 eV between conduction band of and the Fermi energy of the 2DHG 21 , the energy difference between Fermi energy of the 2DHG and the lowest defect measured in this study is 2.4 eV. This is lower than the 3.06 eV of the UV laser but higher than the 1.46 eV of the infrared laser.…”

Au/CdBr2/SiO2/Au Straddling‐Type Heterojunctions Designed as Microwave Multiband Pass Filters, Negative Capacitance Transistors, and Current Rectifiers

“…The values of the conduction and valance band offsets are large enough to nominate the device for use as thin‐film transistors. [ 19,20 ] values of 3.28 eV are shown to be very suitable for p−type metal oxide semiconductor field effect transistor (p−MOSFETS). [ 20 ] It is also noticeable that, as the metal work function of Au is 5.34 eV, Au/CdBr 2 should form Schottky barriers.…”