HfAlO/InAlAs metal-oxide-semiconductor capacitor (MOS capacitor) is considered as the most popular candidate of the isolated gate of InAs/AlSb high electron mobility transistor (HEMT). In order to improve the performa...HfAlO/InAlAs metal-oxide-semiconductor capacitor (MOS capacitor) is considered as the most popular candidate of the isolated gate of InAs/AlSb high electron mobility transistor (HEMT). In order to improve the performance of the HfAlO/InAlAs MOS-capacitor, samples are annealed at different temperatures for investigating the HfAlO/InAlAs interfacial characyeristics and the device's electrical characteristics. We find that as annealing temperature increases from 280 ℃ to 480 ℃, the surface roughness on the oxide layer is improved. A maximum equivalent dielectric constant of 8.47, a minimum equivalent oxide thickness of 5.53 nm, and a small threshold voltage of -1.05 V are detected when being annealed at 380 ℃;furthermore, a low interfacial state density is yielded at 380 ℃, and this can effectively reduce the device leakage current density to a significantly low value of 1×10-7 A/cm2 at 3-V bias voltage. Therefore, we hold that 380 ℃ is the best compromised annealing temperature to ensure that the device performance is improved effectively. This study provides a reliable conceptual basis for preparing and applying HfAlO/InAlAs MOS-capacitor as the isolated gate on InAs/AlSb HEMT devices.展开更多
Interfacial and electrical properties of HfAlO/GaSb metal-oxide-semiconductor capacitors(MOSCAPs) with sulfur passivation were investigated and the chemical mechanisms of the sulfur passivation process were carefully ...Interfacial and electrical properties of HfAlO/GaSb metal-oxide-semiconductor capacitors(MOSCAPs) with sulfur passivation were investigated and the chemical mechanisms of the sulfur passivation process were carefully studied. It was shown that the sulfur passivation treatment could reduce the interface trap density Ditof the HfAlO/GaSb interface by 35% and reduce the equivalent oxide thickness(EOT) from 8 nm to 4 nm. The improved properties are due to the removal of the native oxide layer, as was proven by x-ray photoelectron spectroscopy measurements and high-resolution cross-sectional transmission electron microscopy(HRXTEM) results. It was also found that GaSb-based MOSCAPs with HfAlO gate dielectrics have interfacial properties superior to those using HfO2 or Al2O3 dielectric layers.展开更多
文摘HfAlO/InAlAs metal-oxide-semiconductor capacitor (MOS capacitor) is considered as the most popular candidate of the isolated gate of InAs/AlSb high electron mobility transistor (HEMT). In order to improve the performance of the HfAlO/InAlAs MOS-capacitor, samples are annealed at different temperatures for investigating the HfAlO/InAlAs interfacial characyeristics and the device's electrical characteristics. We find that as annealing temperature increases from 280 ℃ to 480 ℃, the surface roughness on the oxide layer is improved. A maximum equivalent dielectric constant of 8.47, a minimum equivalent oxide thickness of 5.53 nm, and a small threshold voltage of -1.05 V are detected when being annealed at 380 ℃;furthermore, a low interfacial state density is yielded at 380 ℃, and this can effectively reduce the device leakage current density to a significantly low value of 1×10-7 A/cm2 at 3-V bias voltage. Therefore, we hold that 380 ℃ is the best compromised annealing temperature to ensure that the device performance is improved effectively. This study provides a reliable conceptual basis for preparing and applying HfAlO/InAlAs MOS-capacitor as the isolated gate on InAs/AlSb HEMT devices.
基金Project supported by the National Basic Research Program of China （Grant No. 201 ICBA00602） and the National Science and Technology Major Project, China （Grant No. 2011 ZX02708-002）.
文摘Interfacial and electrical properties of HfAlO/GaSb metal-oxide-semiconductor capacitors(MOSCAPs) with sulfur passivation were investigated and the chemical mechanisms of the sulfur passivation process were carefully studied. It was shown that the sulfur passivation treatment could reduce the interface trap density Ditof the HfAlO/GaSb interface by 35% and reduce the equivalent oxide thickness(EOT) from 8 nm to 4 nm. The improved properties are due to the removal of the native oxide layer, as was proven by x-ray photoelectron spectroscopy measurements and high-resolution cross-sectional transmission electron microscopy(HRXTEM) results. It was also found that GaSb-based MOSCAPs with HfAlO gate dielectrics have interfacial properties superior to those using HfO2 or Al2O3 dielectric layers.
