Submicron gate Si₃N₄/AlGaN/GaN-metal-insulator-semiconductor heterostructure field-effect transistors

Effects of interface states and temperature on the C-V behavior of metal/insulator/AlGaN/GaN heterostructure capacitors

“…6,7,12 Nevertheless, Q it ͑V th ͒ and thus ⌬V th are complex functions of D it and temperature in the case of continuous D it ͑E͒.…”

“…While keeping the merits of conventional Schottky-gate-based HFETs, i.e., a high density of two-dimensional electron gas ͑2DEG͒ at the AlGaN/GaN interface, high cutoff and maximum frequencies, and the thermal and chemical stability of AlGaN and GaN, MISHFETs offer many advantages over HFETs, such as lower gate leakage current, higher breakdown voltage, better thermal stability of the gate, mitigation of current collapse, a wider range of gate voltage sweep, and higher maximum drain current and output power. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] These features are crucial for applications in high-power, high-temperature electronics, 7,17 particularly to realize low on-resistance and normally off highpower FETs. 15,18 Although the standard high frequency capacitancevoltage ͑C-V͒ measurement at room temperature ͑RT͒ is usually done on metal/insulator/semiconductor heterostructure ͑MISH͒ capacitors and/or metal/semiconductor heterostructure ͑MSH͒ Schottky diodes before the fabrication and characterization of the MISHFET devices, the C-V data are often used only to estimate the thicknesses of the insulator film and/or the AlGaN layer 1,4,12,16,19 or to calculate the 2DEG density.…”

“…Some other authors have stated that the shifts of the C-V curve and of the threshold voltage ͑V th ͒ with respect to theoretical values are related to the charge in the insulator and at the insulator/AlGaN interface. 6,7,12 The thermal stability of V th has also been proposed as a criterion for high quality insulator/AlGaN interfaces. 10 Surprisingly, little systematic experimental and theoretical study has been done on the high-temperature C-V behavior of MISH capacitors and MSH diodes considering the impact of the interface states.…”

Digital oxide deposition of SiO2 layers for III-nitride metal-oxide-semiconductor heterostructure field-effect transistors

“…While it has been shown that the rf gain and the knee voltage for submicron IGHFETs are the same as those of submicron HFETs, 11 the larger gate-channel separation in the IGHFETs results in stronger short-channel effects. The reduced gate capacitance further makes IGHFETs more vulnerable to the effects of parasitic circuit capacitances.…”

Reduction of current collapse in AlGaN/GaN MISHEMT with bilayer SiN/Al2O3 dielectric gate stack

“…Secondly, the high gate leakage currents that the conventional GaN HEMTs with Schottky metal gates suffer from, that limits the gate voltage swing and thus affecting the maximum output power as well the microwave performance [4,5]. To reduce the gate leakage currents, researchers have tried various gate dielectrics such as SiO 2 [6,7], SiN [8,9], Al 2 O 3 [10], MgO [11], Sc 2 O 3 [12], and ZrO 2 [13]. Among these, the atomic layer deposited (ALD) Al 2 O 3 is one of the most preferred gate dielectric schemes for GaN MISHEMTs [14][15][16][17] with its additional advantages such as wide band gap energy (9 eV), large dielectric constant (k ~ 10), high breakdown field (~10 MV/cm), high thermal and chemical stability.…”