The Al/Si/SiC composites with medium volume fraction for electronic packaging were fabricated by gas pressure infiltration.On the premise of keeping the machinability of the composites,the silicon carbide particles,wh...The Al/Si/SiC composites with medium volume fraction for electronic packaging were fabricated by gas pressure infiltration.On the premise of keeping the machinability of the composites,the silicon carbide particles,which have the similar size with silicon particles（average 13 μm）,were added to replace silicon particles of same volume fraction,and microstructure and properties of the composites were investigated.The results show that reinforcing particles are distributed uniformly and no apparent pores are observed in the composites.It is also observed that higher thermal conductivity（TC） and flexural strength will be obtained with the addition of SiC particles.Meanwhile,coefficient of thermal expansion（CTE） changes smaller than TC.Models for predicting thermal properties were also discussed.Equivalent effective conductivity（EEC） was proposed to make H-J model suitable for hybrid particles and multimodal particle size distribution.展开更多
Si/SiC ceramic composite and lnvar alloy were successfidly joined by vacuum brazing using Ti5OCu-W filler metals into which W was added to release the thermal stress of the brazed joint. Microstructures of the brazed ...Si/SiC ceramic composite and lnvar alloy were successfidly joined by vacuum brazing using Ti5OCu-W filler metals into which W was added to release the thermal stress of the brazed joint. Microstructures of the brazed joints were irwestigated by scanning electron micrascope （SEM） and energy dispersive spectrometer （EDS）. The mechanical properties of the brazed joints were measured by shearing tests. The results showed that the brazed joints were composed of Ti-Cu phase, W phase and Ti-Si phase. W had no effect on the wettability and mobility of the .filler metals. The growth of Ti2 Cu phase was restrained, and the reaction between ceramic composite and filler metals was weakened. The specimen, brazed at 970°C for 5 rain, had the maximum shear strength of 108 MPa at room temperature.展开更多
A novel silicon carbide(SiC) on silicon(Si) heterojunction lateral double-diffused metal-oxide semiconductor fieldeffect transistor with p-type buried layer(PBL Si/SiC LDMOS) is proposed in this paper for the first ti...A novel silicon carbide(SiC) on silicon(Si) heterojunction lateral double-diffused metal-oxide semiconductor fieldeffect transistor with p-type buried layer(PBL Si/SiC LDMOS) is proposed in this paper for the first time.The heterojunction has breakdown point transfer(BPT) characteristics,and the BPT terminal technology is used to increase the breakdown voltage(BV) of Si/SiC LDMOS with the deep drain region.In order to further optimize the surface lateral electric field distribution of Si/SiC LDMOS with the deep drain region,the p-type buried layer is introduced in PBL Si/SiC LDMOS.The vertical electric field is optimized by Si/SiC heterojunction and the surface lateral electric field is optimized by the p-type buried layer,which greatly improves the BV of device and alleviates the relationship between BV and specific on-resistance(R_(on,sp)).Through TCAD simulation,when the drift region length is 20 μm,the BV is significantly improved from 249 V for the conventional Si LDMOS to 440 V for PBL Si/SiC LDMOS,increased by 77%;And the BV is improved from 384 V for Si/SiC LDMOS with the deep drain region to 440 V for the proposed structure,increased by 15%.The figure-of-merit(FOM) of the Si/SiC LDMOS with the deep drain region and PBL Si/SiC LDMOS are 4.26 MW/cm^(2) and 6.37 MW/cm^(2),respectively.For the PBL Si/SiC LDMOS with the drift length of 20 μm,the maximum FOM is 6.86 MW/cm^(2).The PBL Si/SiC LDMOS breaks conventional silicon limit.展开更多
The Si on SiC heterojunction is still poorly understood, although it has a number of potential applications in electronic and optoelectronic devices, for example, light-activated SiC power switches where Si may play t...The Si on SiC heterojunction is still poorly understood, although it has a number of potential applications in electronic and optoelectronic devices, for example, light-activated SiC power switches where Si may play the role of an light absorbing layer. This paper reports on Si films heteroepitaxially grown on the Si face of （0001） n-type 6H-SiC substrates and the use of B2H6 as a dopant for p-Si grown at temperatures in a range of 700-950℃. X-ray diffraction （XRD） analysis and transmission electron microscopy （TEM） tests have demonstrated that the samples prepared at the temperatures ranged from 850℃ to 900℃ are characterized as monocrystalline silicon. The rocking XRD curves show a well symmetry with FWHM of 0.4339° Omega. Twin crystals and stacking faults observed in the epitaxial layers might be responsible for widening of the rocking curves. Dependence of the crystal structure and surface topography on growth temperature is discussed based on the experimental results. The energy band structure and rectifying characteristics of the Si/SiC heterojunctions are also preliminarily tested.展开更多
基金Project (60776019) supported by the National Natural Science Foundation of ChinaProject (61-TP-2010) supported by the Research Fund of the State Key Laboratory of Solidification Processing (NWPU),China
文摘The Al/Si/SiC composites with medium volume fraction for electronic packaging were fabricated by gas pressure infiltration.On the premise of keeping the machinability of the composites,the silicon carbide particles,which have the similar size with silicon particles（average 13 μm）,were added to replace silicon particles of same volume fraction,and microstructure and properties of the composites were investigated.The results show that reinforcing particles are distributed uniformly and no apparent pores are observed in the composites.It is also observed that higher thermal conductivity（TC） and flexural strength will be obtained with the addition of SiC particles.Meanwhile,coefficient of thermal expansion（CTE） changes smaller than TC.Models for predicting thermal properties were also discussed.Equivalent effective conductivity（EEC） was proposed to make H-J model suitable for hybrid particles and multimodal particle size distribution.
文摘Si/SiC ceramic composite and lnvar alloy were successfidly joined by vacuum brazing using Ti5OCu-W filler metals into which W was added to release the thermal stress of the brazed joint. Microstructures of the brazed joints were irwestigated by scanning electron micrascope （SEM） and energy dispersive spectrometer （EDS）. The mechanical properties of the brazed joints were measured by shearing tests. The results showed that the brazed joints were composed of Ti-Cu phase, W phase and Ti-Si phase. W had no effect on the wettability and mobility of the .filler metals. The growth of Ti2 Cu phase was restrained, and the reaction between ceramic composite and filler metals was weakened. The specimen, brazed at 970°C for 5 rain, had the maximum shear strength of 108 MPa at room temperature.
基金Project supported in part by the Science Foundation for Distinguished Young Scholars of Shaanxi Province,China(Grant No.2018JC-017)the 111 Project(Grant No.B12026)。
文摘A novel silicon carbide(SiC) on silicon(Si) heterojunction lateral double-diffused metal-oxide semiconductor fieldeffect transistor with p-type buried layer(PBL Si/SiC LDMOS) is proposed in this paper for the first time.The heterojunction has breakdown point transfer(BPT) characteristics,and the BPT terminal technology is used to increase the breakdown voltage(BV) of Si/SiC LDMOS with the deep drain region.In order to further optimize the surface lateral electric field distribution of Si/SiC LDMOS with the deep drain region,the p-type buried layer is introduced in PBL Si/SiC LDMOS.The vertical electric field is optimized by Si/SiC heterojunction and the surface lateral electric field is optimized by the p-type buried layer,which greatly improves the BV of device and alleviates the relationship between BV and specific on-resistance(R_(on,sp)).Through TCAD simulation,when the drift region length is 20 μm,the BV is significantly improved from 249 V for the conventional Si LDMOS to 440 V for PBL Si/SiC LDMOS,increased by 77%;And the BV is improved from 384 V for Si/SiC LDMOS with the deep drain region to 440 V for the proposed structure,increased by 15%.The figure-of-merit(FOM) of the Si/SiC LDMOS with the deep drain region and PBL Si/SiC LDMOS are 4.26 MW/cm^(2) and 6.37 MW/cm^(2),respectively.For the PBL Si/SiC LDMOS with the drift length of 20 μm,the maximum FOM is 6.86 MW/cm^(2).The PBL Si/SiC LDMOS breaks conventional silicon limit.
基金Project supported by the National Natural Science Foundation of China (Grant No 60576044)
文摘The Si on SiC heterojunction is still poorly understood, although it has a number of potential applications in electronic and optoelectronic devices, for example, light-activated SiC power switches where Si may play the role of an light absorbing layer. This paper reports on Si films heteroepitaxially grown on the Si face of （0001） n-type 6H-SiC substrates and the use of B2H6 as a dopant for p-Si grown at temperatures in a range of 700-950℃. X-ray diffraction （XRD） analysis and transmission electron microscopy （TEM） tests have demonstrated that the samples prepared at the temperatures ranged from 850℃ to 900℃ are characterized as monocrystalline silicon. The rocking XRD curves show a well symmetry with FWHM of 0.4339° Omega. Twin crystals and stacking faults observed in the epitaxial layers might be responsible for widening of the rocking curves. Dependence of the crystal structure and surface topography on growth temperature is discussed based on the experimental results. The energy band structure and rectifying characteristics of the Si/SiC heterojunctions are also preliminarily tested.
