The impacts of remote Coulomb scattering(RCS)on hole mobility in ultra-thin body silicon-on-insulator(UTB SOI)p-MOSFETs at cryogenic temperatures are investigated.The physical models including phonon scattering,surfac...The impacts of remote Coulomb scattering(RCS)on hole mobility in ultra-thin body silicon-on-insulator(UTB SOI)p-MOSFETs at cryogenic temperatures are investigated.The physical models including phonon scattering,surface roughness scattering,and remote Coulomb scatterings are considered,and the results are verified by the experimental results at different temperatures for both bulk(from 300 K to 30 K)and UTB SOI(300 K and 25 K)p-MOSFETs.The impacts of the interfacial trap charges at both front and bottom interfaces on the hole mobility are mainly evaluated for the UTB SOI p-MOSFETs at liquid helium temperature(4.2 K).The results reveal that as the temperature decreases,the RCS due to the interfacial trap charges plays an important role in the hole mobility.展开更多
Ultra-thin barrier(UTB) 4-nm-Al Ga N/Ga N normally-off high electron mobility transistors(HEMTs) having a high current gain cut-off frequency( fT) are demonstrated by the stress-engineered compressive Si N trench tech...Ultra-thin barrier(UTB) 4-nm-Al Ga N/Ga N normally-off high electron mobility transistors(HEMTs) having a high current gain cut-off frequency( fT) are demonstrated by the stress-engineered compressive Si N trench technology.The compressive in-situ Si N guarantees the UTB-Al Ga N/Ga N heterostructure can operate a high electron density of1.27×1013 cm-2, a high uniform sheet resistance of 312.8 Ω/, but a negative threshold for the short-gate devices fabricated on it. With the lateral stress-engineering by full removing in-situ Si N in the 600-nm Si N trench, the short-gated(70 nm) devices obtain a threshold of 0.2 V, achieving the devices operating at enhancement-mode(E-mode). Meanwhile,the novel device also can operate a large current of 610 m A/mm and a high transconductance of 394 m S/mm for the Emode devices. Most of all, a high fT/fmax of 128 GHz/255 GHz is obtained, which is the highest value among the reported E-mode Al Ga N/Ga N HEMTs. Besides, being together with the 211 GHz/346 GHz of fT/fmax for the D-mode HEMTs fabricated on the same materials, this design of E/D-mode with the realization of fmax over 200 GHz in this work is the first one that can be used in Q-band mixed-signal application with further optimization. And the minimized processing difference between the E-and D-mode designs the addition of the Si N trench, will promise an enormous competitive advantage in the fabricating costs.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61674008,61421005,and 61804003)the National Key Research and Development Program of China(Grant No.2016YFA0202101)the China Postdoctoral Science Foundation(Grant Nos.2018M630034 and 2019T120017)。
文摘The impacts of remote Coulomb scattering(RCS)on hole mobility in ultra-thin body silicon-on-insulator(UTB SOI)p-MOSFETs at cryogenic temperatures are investigated.The physical models including phonon scattering,surface roughness scattering,and remote Coulomb scatterings are considered,and the results are verified by the experimental results at different temperatures for both bulk(from 300 K to 30 K)and UTB SOI(300 K and 25 K)p-MOSFETs.The impacts of the interfacial trap charges at both front and bottom interfaces on the hole mobility are mainly evaluated for the UTB SOI p-MOSFETs at liquid helium temperature(4.2 K).The results reveal that as the temperature decreases,the RCS due to the interfacial trap charges plays an important role in the hole mobility.
基金Project supported by the National Key Research and Development Program of China(Grant No.2020YFB1804902)the National Natural Science Foundation of China(Grant No.61904135)+1 种基金the China Postdoctoral Science Foundation(Grant Nos.2018M640957 and BX20200262)the Natural Science Foundation of Shaanxi Province,China(Grant No.2020JQ-316).
文摘Ultra-thin barrier(UTB) 4-nm-Al Ga N/Ga N normally-off high electron mobility transistors(HEMTs) having a high current gain cut-off frequency( fT) are demonstrated by the stress-engineered compressive Si N trench technology.The compressive in-situ Si N guarantees the UTB-Al Ga N/Ga N heterostructure can operate a high electron density of1.27×1013 cm-2, a high uniform sheet resistance of 312.8 Ω/, but a negative threshold for the short-gate devices fabricated on it. With the lateral stress-engineering by full removing in-situ Si N in the 600-nm Si N trench, the short-gated(70 nm) devices obtain a threshold of 0.2 V, achieving the devices operating at enhancement-mode(E-mode). Meanwhile,the novel device also can operate a large current of 610 m A/mm and a high transconductance of 394 m S/mm for the Emode devices. Most of all, a high fT/fmax of 128 GHz/255 GHz is obtained, which is the highest value among the reported E-mode Al Ga N/Ga N HEMTs. Besides, being together with the 211 GHz/346 GHz of fT/fmax for the D-mode HEMTs fabricated on the same materials, this design of E/D-mode with the realization of fmax over 200 GHz in this work is the first one that can be used in Q-band mixed-signal application with further optimization. And the minimized processing difference between the E-and D-mode designs the addition of the Si N trench, will promise an enormous competitive advantage in the fabricating costs.
