High temperature characteristics of doped channel AlGaN/GaN MIS‐HFETs with thin AlGaN barrier layer

Abstract

PACS 72.80. Ey, 73.40.Qv, 85.30.Tv The device performance of AlGaN/GaN-based metal-insulator-semiconductor heterostructure field effect transistors (MIS-HFETs) with a very thin AlGaN barrier and a heavily doped GaN channel for high 2DEG density has been investigated at elevated temperatures up to 250• C. The devices exhibited ultra-low gate current leakages under the reverse gate bias with very reasonable transconductance characteristics at both RT and high temperatures. MIS-HFETs with doped channel showed much higher saturation drain current and weaker current collapse than the conventional devices at RT and high temperatures.

Systematic Study of Insulator Deposition Effect (Si3N4, SiO2, AlN, and Al2O3) on Electrical Properties in AlGaN/GaN Heterostructures

“…Since Si 3 N 4 forms high-quality insulator/nitride interfaces that have low interface state densities, 10,13,21) we can generally expect that high-quality insulator/nitride interfaces can be obtained by inserting a thin Si 3 N 4 layer between the insulator and nitride films, independent of the kind of insulator. In our previous works, [32][33][34][35][36][37]39,40) we proved the validity of this technique in HFETs using an Al 2 O 3 /Si 3 N 4 bilayer gate insulator, where Al 2 O 3 was used as the primary gate insulator. In these works, we succeeded in simultaneously utilizing (i) the high-quality interface between Si 3 N 4 and AlGaN, and (ii) the high resistivity and high dielectric constant of Al 2 O 3 , which is attractive as the gate insulator.…”

“…AlGaN/GaN heterostructure field-effect transistors (HFETs) have recently emerged as promising transistors suitable for high-temperature and high-power microwave applications. [1][2][3][4][5][6][7][8][9] In these GaN-based devices, insulators have proved to be very important constituent materials, because (i) the surface passivation by the insulators is commonly used to suppress the current collapse effect, which is specific to AlGaN/GaN HFETs, [10][11][12] and (ii) insulated-gate HFETs or metal-insulator-semiconductor (MIS) HFETs [14][15][16][17][18][19][21][22][23][24][25][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] are shown to be effective for reducing a large gate leakage current, which is generally observed in AlGaN/GaN HFETs. 13,14) The insulators have thus proved to be important in AlGaN/GaN HFETs, hence, SiO 2 , [15][16][17][18]<...…”

Analysis of electrical properties of insulators (Si3N4, SiO2, AlN, and Al2O3)/0.5 nm Si3N4/AlGaN/GaN heterostructures

“…. In these devices, insulators have proved to be very important constituent materials, because (i) the surface passivation by insulators is commonly used to suppress the current collapse effect, which is specific to AlGaN/GaN HFETs [2], and (ii) the insulated-gate HFETs or the metal-insulator-semiconductor (MIS) HFETs [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] are shown to be effective to reduce the large gate leakage current, which is generally observed in AlGaN/GaN HFETs.Insulators thus play very important roles in AlGaN/GaN HFETs, and hence, understanding the electrical properties of AlGaN/GaN heterostructures with insulators is one of the most fundamental issues to be addressed in understanding and designing the device performance. From this point of view, we have examined the deposition effect of insulators on the electrical properties, and theoretically analyzed the results in terms of the potential profile of the heterostructures with insulators.…”