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

Abstract

We have studied the drain current dispersion characteristics of conventional AlGaN/GaN HEMTs and SiN/Al2O3/AlGaN/GaN metal‐insulator‐semiconductor high electron mobility transistors (MISHEMT) fabricated on silicon substrate. The fabricated MISHEMT exhibited an IDmaxof >1000 mA/mm and gmmax of 241 mS/mm. Compared to conventional AlGaN/GaN HEMTs, about an order of magnitude lower gate leakage current and a ∼ 60% reduction in drain current (ID) collapse was observed in the MISHEMTs. The observation of low ID collapse is due to the occurrence of low interface state density (6.39 × 1010 eV‐1 cm‐2) between the bilayer dielectric (SiN/Al2O3) and GaN surface which is confirmed through the AC‐conductance method. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

AlGaN/GaN MISHEMTs with AlN gate dielectric grown by thermal ALD technique

“…This effect is also described as dynamic behavior degradation, gate lag, drain lag, etc., which is caused by the charge trapping effect on the AlGaN surface especially in the access region between gate and drain [4-6]. In order to solve these two issues, the deposition of oxide-based dielectric such as SiO 2 [7], Al 2 O 3 [8], LaLuO 3 [9], and SrO 2 [10,11] and dielectric stack such as SiN/Al 2 O 3 [12] as gate dielectric layer and passivation layer in the access region simultaneously is widely adopted. But it has been revealed that the introduction of oxide-based dielectric is likely to form Ga-O bond which is thought as one of interface sources leading to current collapse [13].…”

AlGaN/GaN MIS-HEMT with PECVD SiNx, SiON, SiO2 as Gate Dielectric and Passivation Layer

“…Each material has advantages and disadvantages. Some groups studied stack dielectric layers like SiN x /Al 2 O 3 [20] and SiN x /SiO 2 [21] to improve leakage current and stability. The Al 2 O 3 and HfO 2 gate dielectric layer deposited by atomic layer deposition (ALD) has shown advantages in reducing gate leakage and eliminating current collapse [22,23].…”

AlGaN/GaN MISHEMTs with AlN gate dielectric grown by thermal ALD technique

“…This effect is also described as dynamic behavior degradation, gate lag, drain lag, etc., which is caused by the charge trapping effect on the AlGaN surface especially in the access region between gate and drain [4][5][6]. In order to solve these two issues, the deposition of oxide-based dielectric such as SiO 2 [7], Al 2 O 3 [8], LaLuO 3 [9], and SrO 2 [10,11] and dielectric stack such as SiN/Al 2 O 3 [12] as gate dielectric layer and passivation layer in the access region simultaneously is widely adopted. But it has been revealed that the introduction of oxide-based dielectric is likely to form Ga-O bond which is thought as one of interface sources leading to current collapse [13].…”