A 4H-SiC trench gate metal-oxide-semiconductor field-effect transistor(UMOSFET)with semi-super-junction shiel-ded structure(SS-UMOS)is proposed and compared with conventional trench MOSFET(CT-UMOS)in this work.The adv...A 4H-SiC trench gate metal-oxide-semiconductor field-effect transistor(UMOSFET)with semi-super-junction shiel-ded structure(SS-UMOS)is proposed and compared with conventional trench MOSFET(CT-UMOS)in this work.The advantage of the proposed structure is given by comprehensive study of the mechanism of the local semi-super-junction structure at the bottom of the trench MOSFET.In particular,the influence of the bias condition of the p-pillar at the bottom of the trench on the static and dynamic performances of the device is compared and revealed.The on-resistance of SS-UMOS with grounded(G)and ungrounded(NG)p-pillar is reduced by 52%(G)and 71%(NG)compared to CT-UMOS,respectively.Additionally,gate ox-ide in the GSS-UMOS is fully protected by the p-shield layer as well as semi-super-junction structure under the trench and p-base regions.Thus,a reduced electric-field of 2 MV/cm can be achieved at the corner of the p-shield layer.However,the quasi-intrinsic protective layer cannot be formed in NGSS-UMOS due to the charge storage effect in the floating p-pillar,resulting in a large electric field of 2.7 MV/cm at the gate oxide layer.Moreover,the total switching loss of GSS-UMOS is 1.95 mJ/cm2 and is reduced by 18%compared with CT-UMOS.On the contrary,the NGSS-UMOS has the slowest overall switching speed due to the weakened shielding effect of the p-pillar and the largest gate-to-drain capacitance among the three.The proposed GSS-UMOS plays an important role in high-voltage and high-frequency applications,and will provide a valuable idea for device design and circuit applications.展开更多
In Kripke’s theory of truth,the largest intrinsic fixed point—like the least fixed point—is of special theoretical interest among all fixed points.However,for intrinsic yet ungrounded sentences(i.e.,those belonging...In Kripke’s theory of truth,the largest intrinsic fixed point—like the least fixed point—is of special theoretical interest among all fixed points.However,for intrinsic yet ungrounded sentences(i.e.,those belonging to the largest intrinsic fixed points but not to the least fixed point),only sporadic examples have been provided so far,and a universal criterion for deciding such sentences remains unknown.This paper aims to establish a general criterion for determining intrinsic truth in Boolean systems of self-referential sentences under Kleene’s strong valuation scheme.To achieve this,we first present a known result about the definability of three-valued functions within Kleene’s strong logic.Then,by reducing the problem of determining the fixed points to a calculation problem in propositional logic,we demonstrate a truth-functional characteristic for the intrinsic truths in Boolean systems.We thus find an effective method for constructing intrinsic truths in a first-order language for Peano arithmetic.We also discuss the applicability of our findings to Kleene’s weak valuation scheme.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.62104222)the Natural Science Foundation of Fujian Province of China for Distinguished Young Scholars(Grant No.2020J06002)+3 种基金the Science and Technology Project of Fujian Province of China(Grant No.2020I0001)the Science and Technology Key Projects of Xiamen(Grant No.3502ZCQ20191001)Shenzhen Science and Technology Program(Grant No.JSGG20201102-155800003)Jiangxi Provincial Natural Science Foundation(Grant No.20212ACB212005).
文摘A 4H-SiC trench gate metal-oxide-semiconductor field-effect transistor(UMOSFET)with semi-super-junction shiel-ded structure(SS-UMOS)is proposed and compared with conventional trench MOSFET(CT-UMOS)in this work.The advantage of the proposed structure is given by comprehensive study of the mechanism of the local semi-super-junction structure at the bottom of the trench MOSFET.In particular,the influence of the bias condition of the p-pillar at the bottom of the trench on the static and dynamic performances of the device is compared and revealed.The on-resistance of SS-UMOS with grounded(G)and ungrounded(NG)p-pillar is reduced by 52%(G)and 71%(NG)compared to CT-UMOS,respectively.Additionally,gate ox-ide in the GSS-UMOS is fully protected by the p-shield layer as well as semi-super-junction structure under the trench and p-base regions.Thus,a reduced electric-field of 2 MV/cm can be achieved at the corner of the p-shield layer.However,the quasi-intrinsic protective layer cannot be formed in NGSS-UMOS due to the charge storage effect in the floating p-pillar,resulting in a large electric field of 2.7 MV/cm at the gate oxide layer.Moreover,the total switching loss of GSS-UMOS is 1.95 mJ/cm2 and is reduced by 18%compared with CT-UMOS.On the contrary,the NGSS-UMOS has the slowest overall switching speed due to the weakened shielding effect of the p-pillar and the largest gate-to-drain capacitance among the three.The proposed GSS-UMOS plays an important role in high-voltage and high-frequency applications,and will provide a valuable idea for device design and circuit applications.
基金supported by National Social Science Foundation of China,“A Truth-theoretical Study on Limits of Artificial Intelligence”(No.24AZX018)Major Interdisciplinary Cultivation Project of Philosophy and Social Sciences at South China Normal University,“Research on Frontier Issues in Epistemic Logic in Analytic Philosophy.”。
文摘In Kripke’s theory of truth,the largest intrinsic fixed point—like the least fixed point—is of special theoretical interest among all fixed points.However,for intrinsic yet ungrounded sentences(i.e.,those belonging to the largest intrinsic fixed points but not to the least fixed point),only sporadic examples have been provided so far,and a universal criterion for deciding such sentences remains unknown.This paper aims to establish a general criterion for determining intrinsic truth in Boolean systems of self-referential sentences under Kleene’s strong valuation scheme.To achieve this,we first present a known result about the definability of three-valued functions within Kleene’s strong logic.Then,by reducing the problem of determining the fixed points to a calculation problem in propositional logic,we demonstrate a truth-functional characteristic for the intrinsic truths in Boolean systems.We thus find an effective method for constructing intrinsic truths in a first-order language for Peano arithmetic.We also discuss the applicability of our findings to Kleene’s weak valuation scheme.
