SiO₂/AlON stacked gate dielectrics for AlGaN/GaN MOS heterojunction field-effect transistors

Abstract

Stacked gate dielectrics consisting of wide bandgap SiO2 insulators and thin aluminum oxynitride (AlON) interlayers were systematically investigated in order to improve the performance and reliability of AlGaN/GaN metal–oxide–semiconductor (MOS) devices. A significantly reduced gate leakage current compared with that in a single AlON layer was achieved with these structures, while maintaining the superior thermal stability and electrical properties of the oxynitride/AlGaN interface. Consequently, distinct advantages in terms of the reliability of the gate dielectrics, such as an improved immunity against electron injection and an increased dielectric breakdown field, were demonstrated for AlGaN/GaN MOS capacitors with optimized stacked structures having a 3.3-nm-thick AlON interlayer.

Improved Electrical Characteristics of AlGaN/GaN High-Electron-Mobility Transistor with Al2O3/ZrO2 Stacked Gate Dielectrics

“…Strong correlation was observed between different compound contents and microwave dielectric properties [ 19 , 20 ]. Many studies have been widely explored, and excellent results have been obtained [ 21 , 22 , 23 , 24 , 25 ] for GaN-based HEMT; however, the reliability of Al 2 O 3 /ZrO 2 on AlGaN/GaN HEMTs has rarely been evaluated [ 23 ].…”

Partially Crystallized Ultrathin Interfaces between GaN and SiNx Grown by Low-Pressure Chemical Vapor Deposition and Interface Editing

“…The growth and development of high-quality dielectrics is of exceptional importance for their incorporation into next-generation GaN high-electron-mobility transistors (HEMTs) because of their great potential in the radio frequency and power switching applications for both lateral and vertical devices. , The high-quality interface and the high tolerance to the electric stress are the main criteria and underlying challenges to both the material selection and growth. Various materials have been adopted on the (Al)­GaN surface as the passivation and gate dielectric layer to improve the device performance and reliability, such as SiO 2 , SiN x , , AlN, Al 2 O 3 , AlON, , HfO 2 , ZrO 2 , MgGaO, and AlSiO . Among them, SiN x dielectrics grown by low-pressure chemical vapor deposition (LPCVD) demonstrated excellent time-dependent dielectric breakdown (TDDB) properties in GaN MIS-HEMT .…”

“…1,2 The high-quality interface and the high tolerance to the electric stress are the main criteria and underlying challenges to both the material selection and growth. Various materials have been adopted on the (Al)GaN surface as the passivation and gate dielectric layer to improve the device performance and reliability, such as SiO 2 , 3 SiN x , 4,5 AlN, 6 Al 2 O 3 , 7 AlON, 8,9 HfO 2 , 10 ZrO 2 , 11 MgGaO, 12 and AlSiO. 1 Among them, SiN x dielectrics grown by low-pressure chemical vapor deposition (LPCVD) demonstrated excellent timedependent dielectric breakdown (TDDB) properties in GaN MIS-HEMT.…”

Anomalous interface fixed charge generated by forming gas annealing in SiO2/GaN MOS devices

“…SiO 2 , Al 2 O 3 , and their oxynitrides (SiON and AlON) have been studied as gate insulators in GaN MOS structures. [18][19][20][21][22][23] In particular, SiO 2 is promising for GaN MOS structures because of its large band offset relative to the lowest conduction band edge and the highest valence band edge of GaN. As well, a lot of knowledge has been accumulated on SiO 2 /Si MOS devices.…”