Microwave diamond devices technology: Field‐effect transistors and modeling

Abstract

This paper provides an overview of the developments in microwave diamond field-effect transistor (D-FET) technologies. Due to the ultrawide-bandgap and high carrier velocity and thermal conductivity of diamond, it is a potential candidate for microwave power devices with high output power and operating frequency. Here, the properties of semiconductor materials for microwave applications are described. Then, the mechanisms of various diamond FETs are detailed. In recent years, hydrogen-terminated diamond metal-oxidesemiconductor field-effect transistors (HD MOSFETs) have been widely studied for their potential use in microwave power devices. Therefore, the structures and developments of HD MOSFETs are mainly discussed. Finally, in the prospective application of the HD FET microwave circuit, the state-of-the-art large-signal modeling of HD MOSFETs is presented.

Hydrogen-Terminated Diamond MOSFETs Using Ultrathin Glassy Ga2O3 Dielectric Formed by Low-Temperature Liquid Metal Printing Method

“…Wide-band-gap semiconductors, such as GaN, SiC, and diamond, have attracted significant attention for their potential to surpass the limitations of silicon-based technologies. , Due to a combination of extraordinary electronic properties such as high breakdown voltage (>20 MV/cm), high carrier mobilities (4500 cm 2 /(V·s) for electrons and 3800 cm 2 /(V·s) for holes), and high carrier saturation velocities (2.7 × 10 7 cm/s for electrons and 1.1 × 10 7 cm/s for holes), diamond has been long hailed as the ideal material for building the next generation of high-power and high-frequency electronics with performance unattainable by other competing wide-bandgap semiconductors . Although diamond, similar to most wide-band-gap semiconductors, is inherently difficult to be doped due to deep doping levels, the discovery and understanding of the p-type surface conductivity on hydrogen-terminated diamond (H-diamond) induced by either atmospheric acceptors and solid-state surface acceptors − through the so-called surface transfer doping process , have paved the way for making surface-conducting diamond a promising platform to develop diamond-based electronics and spintronics technologies. , The emergence of p-type surface conductivity of H-diamond is particularly attractive for fabricating metal-oxide-semiconductor field-effect transistors (MOSFETs), a basic electronic element at the core of next-generation diamond-based integrated circuits . Indeed, high-performance diamond MOSFETs, formed by exploiting the surface-conducting channel of H-diamond, have been widely reported .…”

“…2,11 The emergence of p-type surface conductivity of H-diamond is particularly attractive for fabricating metaloxide-semiconductor field-effect transistors (MOSFETs), a basic electronic element at the core of next-generation diamond-based integrated circuits. 12 Indeed, high-performance diamond MOSFETs, formed by exploiting the surfaceconducting channel of H-diamond, have been widely reported. 13 Optimizing the quality of the MOSFET dielectrics is critical to enhance the device performance, requiring careful optimization and control factors such as growth technology and dielectric constant.…”

2‐mm‐gate‐periphery GaN high electron mobility transistor s on SiC and Si substrates: A comparative analysis from a small‐signal standpoint

“…The substrate/buffer loading effect could be observed also from the analysis of the frequency dependence of the drain-source and gate-source susceptances divided by angular frequency (ω) (see Figure 1(B)). Contrary to the T A B L E 1 Dislocation density and lattice mismatch for different substrate 6,9 Substrate N DD (cm −2 ) % Lattice mismatch SiC device that exhibits constant values used for extracting the extrinsic pad capacitances, remarkable frequency dependence is observed for the Si device. This could characterize two capacitive effects, which include the typical pad capacitances in addition to capacitances that could be related to the charges in the substrate/ buffer.…”

“…5 GaN-on-Dia HEMT is a recent emerging technology. 6 The thermal conductivity of the diamond substrate is about five times higher than that of the SiC counterpart, 7 resulting in lower self-heating effects and thus better performance in terms of reliability and power efficiency of the transistor. Nevertheless, the performances of the GaN-on-Dia HEMTs are significantly affected by the lattice-mismatch induced threading dislocations, which enhance buffertrapping effects.…”

A scalable electrothermal model using a three‐dimensional thermal analysis model forGaN‐on‐diamondhigh‐electron‐mobility transistors

“…As a result, the device maintains a lower temperature, even if power consumption increases. Such devices also prove more reliable and efficient 21 …”