- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Temperature dependent control of the solubility of gallium nitride in supercritical ammonia using mixed mineralizer
摘要： Using a mass-loss method, we investigated the solubility change of gallium nitride (GaN) in supercritical ammonia with mixed mineralizers [ammonium chloride (NH4Cl) + ammonium bromide (NH4Br) and NH4Cl + ammonium iodide (NH4I)]. The solubilities were measured over the temperature range 450–550 °C, at 100 MPa. The solubility increased with NH4Cl mole fraction at 450 °C and 100 MPa. The temperature dependence of the solubility curve was then measured at an equal mole ratio of the two mineralizers. The slope of the solubility–temperature relationship in the mixed mineralizer was between those of the individual mineralizers. These results show that the temperature dependence of the solubility of GaN can be controlled by the mineralizer mixture ratio. The results of the van’t Hoff plot suggest that the solubility species were unchanged over the investigated temperature range. Our approach might pave the way to realizing large, high-quality GaN crystals for future gallium-nitride electronic devices, which are increasingly on demand in the information-based age.
关键词： Acidic mineralizer,Gallium nitride,Ammonothermal,Solubility,Supercritical ammonia
更新于2025-09-19 17:15:36
-
Vertical GaN n-channel MISFETs on ammonothermal GaN substrate: Temperature dependent dynamic switching characteristics
摘要： Switching of GaN-based vertical-trench gate MISFET on ammonothermal n-type GaN substrate are studied as a function of temperature. Pulsed ON-state IV characterization revealed three unexpected independent effects. First, drain current increases with temperature, although electron mobility decreases with temperature. Second, drain current decreases with pulse length, which cannot be explained by heating. Third, dynamic RON increases with OFF-state drain bias, which usually is considered as an issue of lateral GaN HFETs only. The drain current temperature dependence is most likely dominated by the low electron mobility in the inversion layer beneath the gate. The field effect channel mobility is estimated as < 10 cm2/V s and can thus be considered as trap limited and thermally activated, RON decreases from 133 Ω mm at 20 °C to 62 Ω mm at 110 °C. Longer ON-state pulses lead to negative charging of the ALD-Al2O3 gate oxide and shift the threshold voltage (DC-Vth ~8 V) positively. With the maximum applicable Vgs = 10 V, the drain current is not saturated yet and Ids thus drops by a factor 2 when increasing the ON-state pulse width from 0.2 μs to 20 μs due to the Vth-shift. The observed 10-times dynamic RON increase with OFF-state drain bias up to 30 V can be related to possible charging mechanism in the gate oxide as well. Activation energies for different OFF-state stress voltage are ranged linear between 0.08 eV and 0.26 eV for drain bias stress of Vds = 0 V and 30 V respectively.
关键词： Vertical GaN MISFET,Dynamic switching,Ammonothermal GaN substrate
更新于2025-09-10 09:29:36