Luxshare ICT (China)

Continuous sign language recognition has received widespread attention in the field of human-computer interaction. Compared with optical camera based continuous sign language recognition systems, millimeter wave radar based sign language recognition systems have unique advantages such as high integration, all-weather operation, and robustness in low light environments. This study constructed a continuous Chinese sign language recognition method using 60GHz Doppler radar, which utilizes a convolutional neural network incorporating Efficient Channel Attention (ECA) to process radar micro Doppler signals. A sign language radar data acquisition device was established on the Doppler radar, and 20 commonly used sign language statements for train stations were collected in the time-frequency domain to form a dataset. Subsequently, these data were input into the proposed neural network model for recognition and classification. The experiment shows that the proposed system achieves an accuracy of 97.92% in recognizing sign language at train stations. Compared with other radar based sign language recognition systems, the proposed system exhibits higher recognition accuracy.

In this work, we investigated the stability of a <inline-formula> <tex-math notation="LaTeX">${p}$ </tex-math></inline-formula>-GaN gate with high electron mobility transistors (HEMTs) including an internal integrated gate circuit. A circuit was designed to improve <inline-formula> <tex-math notation="LaTeX">${p}$ </tex-math></inline-formula>-GaN gate stability by using capacitance to release the hole into the <inline-formula> <tex-math notation="LaTeX">${p}$ </tex-math></inline-formula>-GaN layer to mitigate the threshold voltage shift. Through pulse I-V measurement and positive bias temperature instability (PBTI) test, the carrier transporting behavior in the gate region achieved dynamic equilibrium at 5 V gate bias. The positive gate shift <inline-formula> <tex-math notation="LaTeX">$(\Delta V_{\mathrm{ TH}})$ </tex-math></inline-formula> of 0.4 V is observed with increasing voltage from 3 V to 8 V; <inline-formula> <tex-math notation="LaTeX">$\Delta V_{\mathrm{ TH}}$ </tex-math></inline-formula> initially drops smoothly after release stresses by external capacitance discharge. Finally, integrated passive components and <inline-formula> <tex-math notation="LaTeX">${p}$ </tex-math></inline-formula>-GaN gate HEMT circuit are recommended to mitigate the <inline-formula> <tex-math notation="LaTeX">$V_{\mathrm{ TH}}$ </tex-math></inline-formula> instability for E-mode HEMT.

In this article, an ohmic contact structure based on indium tin oxide (ITO)/Ti/Al/Ni/Au is explored for high-performance GaN-on-GaN Schottky barrier diode (SBD) for the first time. Owing to the ultrathin ITO interfacial layer, the Fermi-level pinning (FLP) effect in metal-semiconductor interface could be mitigated, thus the specific contact resistivity ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\rho _{c}{)}$ </tex-math></inline-formula> on N-polarity was reduced from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.32\times 10^{-{3}}$ </tex-math></inline-formula> to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$7.36\times 10^{-{5}}\,\,\Omega $ </tex-math></inline-formula> cm2, and the specific ON-resistance ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}_{\text {ON}}{)}$ </tex-math></inline-formula> of the device was reduced from 3.14 to 1.17 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{m}\Omega $ </tex-math></inline-formula> cm2 under the same testing condition. With the Helium ion implantation technology, a high breakdown voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {BR}}{)}$ </tex-math></inline-formula> of 1100 V, low turn-on voltage <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {ON}}$ </tex-math></inline-formula> of 0.63 V, and a high figure of merit ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {BR}}^{{2}}/{R}_{\text {ON}}{)}$ </tex-math></inline-formula> of 1.04 GW/cm2 were achieved in this work. The vertical GaN SBD with ITO interfacial layer fabricated in this work achieved the lowest <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\rho _{c}$ </tex-math></inline-formula> in the reported GaN-on-GaN SBDs with an indicated anode size.