In this paper, an analytical model for the vertical electric field distribution and optimization of a high voltage-reduced bulk field（REBULF） lateral double-diffused metal–oxide-semiconductor（LDMOS） transistor is...In this paper, an analytical model for the vertical electric field distribution and optimization of a high voltage-reduced bulk field（REBULF） lateral double-diffused metal–oxide-semiconductor（LDMOS） transistor is presented. The dependences of the breakdown voltage on the buried n-layer depth, thickness, and doping concentration are discussed in detail.The REBULF criterion and the optimal vertical electric field distribution condition are derived on the basis of the optimization of the electric field distribution. The breakdown voltage of the REBULF LDMOS transistor is always higher than that of a single reduced surface field（RESURF） LDMOS transistor, and both analytical and numerical results show that it is better to make a thick n-layer buried deep into the p-substrate.展开更多
A new super-junction lateral double diffused MOSFET （LDMOST） structure is designed with n-type charge compensation layer embedded in the p^--substrate near the drain to suppress substrate-assisted depletion effect t...A new super-junction lateral double diffused MOSFET （LDMOST） structure is designed with n-type charge compensation layer embedded in the p^--substrate near the drain to suppress substrate-assisted depletion effect that results from the compensating charges imbalance between the pillars in the n-type buried layer. A high electric field peak is introduced in the surface by the pn junction between the p^--substrate and n-type buried layer, which given rise to a more uniform surface electric field distribution by modulation effect. The effect of reduced bulk field （REBULF） is introduced to improve the vertical breakdown voltage by reducing the high bulk electric field around the drain, The new structure features high breakdown voltage, low on-resistance and charges balance in the drift region due to n-type buried layer.展开更多
A novel triple RESURF（T-resurf） SOI LDMOS structure is proposed.This structure has a P-type buried layer.Firstly,the depletion layer can extend on both sides of the P-buried layer,serving as a triple RESURF and lead...A novel triple RESURF（T-resurf） SOI LDMOS structure is proposed.This structure has a P-type buried layer.Firstly,the depletion layer can extend on both sides of the P-buried layer,serving as a triple RESURF and leading to a high drift doping and a low on-resistance.Secondly,at a high doping concentration of the drift region, the P-layer can reduce high bulk electric field in the drift region and enhance the vertical electric field at the drain side,which results in uniform bulk electric field distributions and an enhanced BV.The proposed structure is used in SOI devices for the first time.The T-resurf SOI LDMOS with BV = 315 V is obtained by simulation on a 6μm-thick SOI layer over a 2μm-thick buried oxide layer,and its R_（sp） is reduced from 16.5 to 13.8 mΩ·cm^2 in comparison with the double RESURF（D-resurf） SOI LDMOS.When the thickness of the SOI layer increases, T-resurf SOI LDMOS displays a more obvious effect on the enhancement of BV^2/R_（on）.It reduces R_（sp） by 25%in 400 V SOI LDMOS and by 38%in 550 V SOI LDMOS compared with the D-resurf structure.展开更多
基金Project supported by the Scientific Research Fund of Education Department of Sichuan Province,China(Grant No.14ZB0132)the Key Project of Xihua University,China(Grant No.z1323318)
文摘In this paper, an analytical model for the vertical electric field distribution and optimization of a high voltage-reduced bulk field（REBULF） lateral double-diffused metal–oxide-semiconductor（LDMOS） transistor is presented. The dependences of the breakdown voltage on the buried n-layer depth, thickness, and doping concentration are discussed in detail.The REBULF criterion and the optimal vertical electric field distribution condition are derived on the basis of the optimization of the electric field distribution. The breakdown voltage of the REBULF LDMOS transistor is always higher than that of a single reduced surface field（RESURF） LDMOS transistor, and both analytical and numerical results show that it is better to make a thick n-layer buried deep into the p-substrate.
基金Project supported by the National Natural Science Foundation of China （Grant No 60436030） and the Key Laboratory for Defence Science and Technology on Military Simulation Integrated Circuits （Grant No 9140C0903010604）.
文摘A new super-junction lateral double diffused MOSFET （LDMOST） structure is designed with n-type charge compensation layer embedded in the p^--substrate near the drain to suppress substrate-assisted depletion effect that results from the compensating charges imbalance between the pillars in the n-type buried layer. A high electric field peak is introduced in the surface by the pn junction between the p^--substrate and n-type buried layer, which given rise to a more uniform surface electric field distribution by modulation effect. The effect of reduced bulk field （REBULF） is introduced to improve the vertical breakdown voltage by reducing the high bulk electric field around the drain, The new structure features high breakdown voltage, low on-resistance and charges balance in the drift region due to n-type buried layer.
基金Project supported by the National Natural Science Foundation of China(Nos.60806025,60976060)
文摘A novel triple RESURF（T-resurf） SOI LDMOS structure is proposed.This structure has a P-type buried layer.Firstly,the depletion layer can extend on both sides of the P-buried layer,serving as a triple RESURF and leading to a high drift doping and a low on-resistance.Secondly,at a high doping concentration of the drift region, the P-layer can reduce high bulk electric field in the drift region and enhance the vertical electric field at the drain side,which results in uniform bulk electric field distributions and an enhanced BV.The proposed structure is used in SOI devices for the first time.The T-resurf SOI LDMOS with BV = 315 V is obtained by simulation on a 6μm-thick SOI layer over a 2μm-thick buried oxide layer,and its R_（sp） is reduced from 16.5 to 13.8 mΩ·cm^2 in comparison with the double RESURF（D-resurf） SOI LDMOS.When the thickness of the SOI layer increases, T-resurf SOI LDMOS displays a more obvious effect on the enhancement of BV^2/R_（on）.It reduces R_（sp） by 25%in 400 V SOI LDMOS and by 38%in 550 V SOI LDMOS compared with the D-resurf structure.
