AlN/GaN Superlattice Channel HEMTs on Silicon Substrate

High-electron-mobility transistor (HEMT) with AlN/GaN superlattice (SL) channel has been demonstrated on a silicon substrate. High OFF-state breakdown voltage V-BR of 670 V (gate-drain spacing L-GD = 8 mu m) along with a maximum output current of 196 mA/mm, a channel electron total mobility of 507 cm(2)/V center dot s, and an ON/OFF ratio of over 107 was achieved in this novel HEMT. For the HEMT with LGD = 22 mu m, a high VBR of 1700 V was obtained with substrate floated. The influence of LGD, the gate-source voltage VGS, the isolated pattern, and substrate grounded and floated type was discussed to analyze the breakdown characteristics of HEMT. We investigated the trap states in the AlN/GaN SL channel of HEMTs by frequency-dependent capacitance and conductance measurements. A trap state density of 7.4 x 10(12)-1.2 x 10(13) cm(-2)eV(-1) is located at ET in a range of 0.29-0.33 eV of the main channel, while the trap state density in the parasitic channel decreases from 3.9 x 10(11) cm(-2)eV(-1) at an energy of 0.27 eV to 1.1 x 10(11) cm(-2)eV(-1) at an energy of 0.38 eV. The fabricated AlN/GaN SL channel HEMTs in this work reveal a great step toward the realization of the SL channel HEMTs on cost-effective silicon substrate and provide a novel technology for AlGaN multichannel devices to obtain high output current.

Automated summary

A high-electron-mobility transistor (HEMT) with AlN/GaN superlattice (SL) channel has been successfully demonstrated on a silicon substrate, achieving high performance with optimized breakdown voltage and output current. The trap states in the AlN/GaN SL channel were investigated, revealing a reduction in trap state density in the parasitic channel and specific energy levels in the main channel. This study represents a significant advancement in the development of SL channel HEMTs on cost-effective silicon substrates and provides a novel technology for high output current in AlGaN multichannel devices.