Tri-Gate Normally-Off GaN Power MISFET

Current Stability in Multi-Mesa-Channel AlGaN/GaN HEMTs

“…In addition, we have found that the MMC structure demonstrates lower off-state-stress-induced current collapse [29]. Very recently, similar device structures were reported by Liu et al [30] and Lu et al [31]. They demonstrated a similar V TH shift and good normally-off operation in nano-channel array AlGaN/GaN HEMTs [30] and tri-gate GaN metal-insulator-semiconductor field-effect transistors [31] …”

“…5(a) indicated that the metal/2DEG interface at the side wall does not cause severe leakage current. Lu et al [31] also reported relatively low gate leakage currents for a similar device structure. In the MMC HEMTs, improvement of the subthreshold slope was observed with narrowing of the mesa-top width.…”

“…As the mesa-top width was decreased, a systematic shift of the threshold voltage (V TH ) toward the positive voltage direction was observed in MMC HEMTs. In particular, the MMC HEMT with W top = 50 nm showed a V TH nearly equal to 0 V. Liu et al [30] and Lu et al [31] reported a similar V TH shift and good normally-off operation in nano-channel array AlGaN/GaN HEMTs and tri-gate GaN metal-insulator-semiconductor field-effect transistors, respectively. The gate leakage currents are also plotted by broken lines.…”

A Technology Overview of the PowerChip Development Program

“…To significantly reduce the leakage current in high voltage transistors, it is important to have excellent electrostatic confinement of the channel electrons. For this, we have recently demonstrated a trigate technology that divides the transistor channel into thousands of parallel nanoribbons which are then wrapped by the gate electrode both on the top and on the sidewalls [93]. This technology, when combined with the dual-gate E-mode technology, significantly reduces the drain leakage current of the transistors as shown in Fig.…”

Breaking Through the Multi-Mesa-Channel Width Limited of Normally Off GaN HEMTs Through Modulation of the Via-Hole-Length

“…Although they have many attractive properties, AlGaN/ GaN high-electron-mobility transistors (HEMTs) have not found universal utility because their electronic characteristics can require complex circuit configurations for digital, power, RF, and microwave circuit applications. Accordingly, normally off operation would be essential for any future III-V semiconductor devices [10,11]. Although some special fabrication techniques have been tested (e.g., use of recessed gates [12][13][14], insertion of p-type capping layers under the gate [15,16], tunnel junction structures [17], fluoride ion implantation into the barrier under the gate [18], and inclusion of thin AlGaN barrier layers with a special metal gate and rapid thermal annealing (RTA) treatment [19]), they can worsen device performance and cause stability issues through processing-induced material damage and increased thermal and electric field effects.…”