Advanced materials (Deerfield Beach, Fla.), Jan 2, 2016
Monolithic 3D integrated circuits using transition metal dichalcogenide materials using low tempe... more Monolithic 3D integrated circuits using transition metal dichalcogenide materials using low temperature processing are reported. A variety of digital and analog circuits are implemented on two sequentially integrated layers of devices. Inverter circuit operation at ultra-low supply voltage of 150 mV is achieved paving way for high-density, ultra-low-voltage, and ultra-low-power applications.
The effect of the negative substrate bias (V sub) on the device performance of the InAlN/GaN meta... more The effect of the negative substrate bias (V sub) on the device performance of the InAlN/GaN metal–insulator–semiconductor high-electron-mobility transistors (MIS-HEMTs) is studied. When the V sub decreased from 0 V to −40 V, the two-dimensional electron gas (2DEG) electron density (n 2D) under the gate region decreased, while the 2DEG electron mobility (µ 2DEG) under the gate region was significantly improved. Due to the InGaN back barrier layer and the thin GaN channel layer (15 nm), the 2DEG electrons in the channel are injected into the InGaN back barrier layer with negative V sub, leading to the decreased n 2D. The decrease of the n 2D caused the decrease of the collision probability between the polar optical phonon (POP) and the 2DEG electrons, and the enlarged distance between the 2DEG electrons and the AlN/GaN interface, resulting in the weaker POP and interface roughness scatterings and higher µ 2DEG. This provides a possible way to increase 2DEG electron mobility and further improve the device performance of InAlN/GaN MIS-HEMTs.
In this letter, we present the electrical properties of the InAlN/GaN metal-insulator-semiconduct... more In this letter, we present the electrical properties of the InAlN/GaN metal-insulator-semiconductor high-electron-mobility transistor (MISHEMT) with plasma enhanced atomic layer-deposited ZrO2 as the gate dielectric. The InAlN/GaN MISHEMT with an on/off current (Ion/Ioff) ratio of 1.46×109 as well as a subthreshold swing (SS) of 85 mV/dec was achieved. The interface trap density (Dit) decreased from 1.16 × 1012 eV-1cm-2 (at EC-ET = 0.26 eV) to 4.68 × 1011 eV-1cm-2 (at EC-ET = 0.40 eV), indicating a good interface property. This study suggests a feasible way for the application of ZrO2/InAlN/GaN MISHEMTs
ABSTRACT In response to the continually increasing appetite for bandwidth, most transistor techno... more ABSTRACT In response to the continually increasing appetite for bandwidth, most transistor technologies have recently made great strides towards higher cutoff frequencies: Silicon MOSFETs, SiGe HBTs, InP-based HEMTs and a variety of InP -based HBTs all show cutoff frequencies fT and/or fMAX exceeding 300 GHz, and in some cases approaching 800 GHz. Proponents of various technologies have stated that the development of THz bandwidth devices is an attainable milestone for their technology of choice. Such ambitious goals naturally raise the question of whether such performances are in fact realistic given the well-known trends relating breakdown voltages and cutoff frequencies. Can the contending technologies be scaled in a way enabling THz cutoff frequencies while maintaining the well-behaved characteristics of less aggressively scaled previous generations? The present Invited Paper focuses on our efforts to push InP/GaAsSb DHBTs toward THz bandwidths.
Advanced materials (Deerfield Beach, Fla.), Jan 2, 2016
Monolithic 3D integrated circuits using transition metal dichalcogenide materials using low tempe... more Monolithic 3D integrated circuits using transition metal dichalcogenide materials using low temperature processing are reported. A variety of digital and analog circuits are implemented on two sequentially integrated layers of devices. Inverter circuit operation at ultra-low supply voltage of 150 mV is achieved paving way for high-density, ultra-low-voltage, and ultra-low-power applications.
The effect of the negative substrate bias (V sub) on the device performance of the InAlN/GaN meta... more The effect of the negative substrate bias (V sub) on the device performance of the InAlN/GaN metal–insulator–semiconductor high-electron-mobility transistors (MIS-HEMTs) is studied. When the V sub decreased from 0 V to −40 V, the two-dimensional electron gas (2DEG) electron density (n 2D) under the gate region decreased, while the 2DEG electron mobility (µ 2DEG) under the gate region was significantly improved. Due to the InGaN back barrier layer and the thin GaN channel layer (15 nm), the 2DEG electrons in the channel are injected into the InGaN back barrier layer with negative V sub, leading to the decreased n 2D. The decrease of the n 2D caused the decrease of the collision probability between the polar optical phonon (POP) and the 2DEG electrons, and the enlarged distance between the 2DEG electrons and the AlN/GaN interface, resulting in the weaker POP and interface roughness scatterings and higher µ 2DEG. This provides a possible way to increase 2DEG electron mobility and further improve the device performance of InAlN/GaN MIS-HEMTs.
In this letter, we present the electrical properties of the InAlN/GaN metal-insulator-semiconduct... more In this letter, we present the electrical properties of the InAlN/GaN metal-insulator-semiconductor high-electron-mobility transistor (MISHEMT) with plasma enhanced atomic layer-deposited ZrO2 as the gate dielectric. The InAlN/GaN MISHEMT with an on/off current (Ion/Ioff) ratio of 1.46×109 as well as a subthreshold swing (SS) of 85 mV/dec was achieved. The interface trap density (Dit) decreased from 1.16 × 1012 eV-1cm-2 (at EC-ET = 0.26 eV) to 4.68 × 1011 eV-1cm-2 (at EC-ET = 0.40 eV), indicating a good interface property. This study suggests a feasible way for the application of ZrO2/InAlN/GaN MISHEMTs
ABSTRACT In response to the continually increasing appetite for bandwidth, most transistor techno... more ABSTRACT In response to the continually increasing appetite for bandwidth, most transistor technologies have recently made great strides towards higher cutoff frequencies: Silicon MOSFETs, SiGe HBTs, InP-based HEMTs and a variety of InP -based HBTs all show cutoff frequencies fT and/or fMAX exceeding 300 GHz, and in some cases approaching 800 GHz. Proponents of various technologies have stated that the development of THz bandwidth devices is an attainable milestone for their technology of choice. Such ambitious goals naturally raise the question of whether such performances are in fact realistic given the well-known trends relating breakdown voltages and cutoff frequencies. Can the contending technologies be scaled in a way enabling THz cutoff frequencies while maintaining the well-behaved characteristics of less aggressively scaled previous generations? The present Invited Paper focuses on our efforts to push InP/GaAsSb DHBTs toward THz bandwidths.
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Papers by Yuping Zeng