Highly oriented voids-free 3C-SiC heteroepitaxial layers are grown onφ50mm Si (100) substrates by low pressure chemical vapor deposition (LPCVD).The initial stage of carbonization and the surface morphology of carbon...Highly oriented voids-free 3C-SiC heteroepitaxial layers are grown onφ50mm Si (100) substrates by low pressure chemical vapor deposition (LPCVD).The initial stage of carbonization and the surface morphology of carbonization layers of Si (100) are studied using reflection high energy electron diffraction (RHEED) and scanning electron microscopy (SEM).It is shown that the optimized carbonization temperature for the growth of voids-free 3C-SiC on Si (100) substrates is 1100℃.The electrical properties of SiC layers are characterized using Van der Pauw method.The I-V,C-V,and the temperature dependence of I-V characteristics in n-3C-SiC/p-Si heterojunctions with AuGeNi and Al electrical pads are investigated.It is shown that the maximum reverse breakdown voltage of the n-3C-SiC/p-Si heterojunction diodes reaches to 220V at room temperature.These results indicate that the SiC/Si heterojunction diode can be used to fabricate the wide bandgap emitter SiC/Si heterojunction bipolar transistors (HBT's).展开更多
The ZnO/Si heterojunction diode can be integrated with the Si process, which has attracted great attention in recent years. However, the large number of interface states at the ZnO/Si heterojunction interface could ad...The ZnO/Si heterojunction diode can be integrated with the Si process, which has attracted great attention in recent years. However, the large number of interface states at the ZnO/Si heterojunction interface could adversely affect its optoelectronic properties. Here, n-type ZnO thin film was deposited on p-Si substrate for formation of an n-ZnO/p-Si heterojunction substrate. To passivate the ZnO/Si interface, a thin Cul film interface passivation layer was inserted at the ZnO/p-Si heterojunction interface. Electrical characterization such as I-V and C-V characteristic curves confirmed the significant improvement of the heterojunction properties e.g. enhancement of forward current injection, reduction of reverse current and improvement of the rectification ratio. These results showed that the passivation of interface is critical for ZnO/Si heterojunctions.展开更多
Heteroepitaxial undoped ZnO films were grown on Si （100） substrates by radio-frequency reactive sputtering, and then some of the samples were annealed at N2-800℃ （Sample 1, S1） and 02-800℃ （Sample 2, S2） for 1...Heteroepitaxial undoped ZnO films were grown on Si （100） substrates by radio-frequency reactive sputtering, and then some of the samples were annealed at N2-800℃ （Sample 1, S1） and 02-800℃ （Sample 2, S2） for 1 h, respectively. The electrical transport characteristics of a ZnO/p-Si heterojunction were investigated. We found two interesting phenomena. First, the temperature coefficients of grain boundary resistances of S 1 were positive （positive temperature coefficients, PTC） while that of both the as-grown sample and S2 were negative （negative temperature coefficients, NTC）. Second, the I-V properties of S2 were similar to those common p-n junctions while that of both the as-grown sample and S 1 had double Schottky barrier behaviors, which were in contradiction with the ideal p-n heterojunction model. Combined with the deep level transient spectra results, this revealed that the concentrations of intrinsic defects in ZnO grains and the densities of interfacial states in ZnO/p-Si heterojunction varied with the different annealing ambiences, which caused the grain boundary barriers in ZnO/p-Si heterojunction to vary. This resulted in adjustment electrical properties ofZnO/p-Si heterojunction that may be suitable in various applications.展开更多
The D0h luminescence of ZnO films deposited on p-type Si substrates is produced by metal-organic chemical vapor deposition(MOCVD).After annealing in the air at 700°C for an hour,the photoluminescence(PL)spectra,t...The D0h luminescence of ZnO films deposited on p-type Si substrates is produced by metal-organic chemical vapor deposition(MOCVD).After annealing in the air at 700°C for an hour,the photoluminescence(PL)spectra,the I-V characteristics and the deep level transient spectroscopy(DLTS)of the samples are measured.All the samples have a rectification characteristic.DLTS signals show two deep levels of E1 and E2.The Gaussian fit curves of the PL spectra at room temperature show three luminescence lines b,c and d,of which b is attributed to the exciton emission.The donor level E1 measured by DLTS and the location state donor ionization energy Ed of the closely neighboring emission lines c and d are correlated.E1 is judged as neutral donor bound to hole emission(D0h).Moreover,the intensity of the PL spectra decreases while the relative density of E2 increases,showing that E2 has the property of a nonradiative center.展开更多
文摘Highly oriented voids-free 3C-SiC heteroepitaxial layers are grown onφ50mm Si (100) substrates by low pressure chemical vapor deposition (LPCVD).The initial stage of carbonization and the surface morphology of carbonization layers of Si (100) are studied using reflection high energy electron diffraction (RHEED) and scanning electron microscopy (SEM).It is shown that the optimized carbonization temperature for the growth of voids-free 3C-SiC on Si (100) substrates is 1100℃.The electrical properties of SiC layers are characterized using Van der Pauw method.The I-V,C-V,and the temperature dependence of I-V characteristics in n-3C-SiC/p-Si heterojunctions with AuGeNi and Al electrical pads are investigated.It is shown that the maximum reverse breakdown voltage of the n-3C-SiC/p-Si heterojunction diodes reaches to 220V at room temperature.These results indicate that the SiC/Si heterojunction diode can be used to fabricate the wide bandgap emitter SiC/Si heterojunction bipolar transistors (HBT's).
基金Project supported by the "333 High-Level Talents Training Project" in Jiangsu Province of China(No.BRA2016111)the Qing Lan Project of Jiangsu Higher Education+2 种基金the Science and Technology Program of Changzhou(No.CE20175031)the Jiangsu Province Key R&D Projects(No.BE2016200)the High-Tech Key Laboratory of Changzhou(No.CM20173003)
文摘The ZnO/Si heterojunction diode can be integrated with the Si process, which has attracted great attention in recent years. However, the large number of interface states at the ZnO/Si heterojunction interface could adversely affect its optoelectronic properties. Here, n-type ZnO thin film was deposited on p-Si substrate for formation of an n-ZnO/p-Si heterojunction substrate. To passivate the ZnO/Si interface, a thin Cul film interface passivation layer was inserted at the ZnO/p-Si heterojunction interface. Electrical characterization such as I-V and C-V characteristic curves confirmed the significant improvement of the heterojunction properties e.g. enhancement of forward current injection, reduction of reverse current and improvement of the rectification ratio. These results showed that the passivation of interface is critical for ZnO/Si heterojunctions.
基金Project supported by the National Natural Science Foundation of China(Nos.50472009,10474091,50532070)
文摘Heteroepitaxial undoped ZnO films were grown on Si （100） substrates by radio-frequency reactive sputtering, and then some of the samples were annealed at N2-800℃ （Sample 1, S1） and 02-800℃ （Sample 2, S2） for 1 h, respectively. The electrical transport characteristics of a ZnO/p-Si heterojunction were investigated. We found two interesting phenomena. First, the temperature coefficients of grain boundary resistances of S 1 were positive （positive temperature coefficients, PTC） while that of both the as-grown sample and S2 were negative （negative temperature coefficients, NTC）. Second, the I-V properties of S2 were similar to those common p-n junctions while that of both the as-grown sample and S 1 had double Schottky barrier behaviors, which were in contradiction with the ideal p-n heterojunction model. Combined with the deep level transient spectra results, this revealed that the concentrations of intrinsic defects in ZnO grains and the densities of interfacial states in ZnO/p-Si heterojunction varied with the different annealing ambiences, which caused the grain boundary barriers in ZnO/p-Si heterojunction to vary. This resulted in adjustment electrical properties ofZnO/p-Si heterojunction that may be suitable in various applications.
基金supported by the National Natural Science Foundation of China (Grant Nos.50472009,10474091)the Knowledge Innovation Engineering of the Chinese Academy of Sciences (kjcx2-sw-04-02).
文摘The D0h luminescence of ZnO films deposited on p-type Si substrates is produced by metal-organic chemical vapor deposition(MOCVD).After annealing in the air at 700°C for an hour,the photoluminescence(PL)spectra,the I-V characteristics and the deep level transient spectroscopy(DLTS)of the samples are measured.All the samples have a rectification characteristic.DLTS signals show two deep levels of E1 and E2.The Gaussian fit curves of the PL spectra at room temperature show three luminescence lines b,c and d,of which b is attributed to the exciton emission.The donor level E1 measured by DLTS and the location state donor ionization energy Ed of the closely neighboring emission lines c and d are correlated.E1 is judged as neutral donor bound to hole emission(D0h).Moreover,the intensity of the PL spectra decreases while the relative density of E2 increases,showing that E2 has the property of a nonradiative center.
