In order to fabricate strained-Si MOSFETs,we present a method to prepare strained-Si material with highquality surface and ultra-thin SiGe virtual substrate.By sandwiching a low-temperature Si（LT-Si） layer between a...In order to fabricate strained-Si MOSFETs,we present a method to prepare strained-Si material with highquality surface and ultra-thin SiGe virtual substrate.By sandwiching a low-temperature Si（LT-Si） layer between a Si buffer and a pseudomorphic Si_（0.8）Ge_（0.2） layer,the surface roughness root mean square（RMS） is 1.02 nm and the defect density is 10~6 cm^（-2） owing to the misfit dislocations restricted to the LT-Si layer and the threading dislocations suppressed from penetrating into the Si_（0.8）Ge_（0.2） layer.By employing P~＋ implantation and rapid thermal annealing, the strain relaxation degree of the Si_（0.8）Ge_（0.2） layer increases from 85.09%to 96.41%and relaxation is more uniform. Meanwhile,the RMS（1.1nm） varies a little and the defect density varies little.According to the results,the method of combining an LT-Si layer with ion implantation can prepare high-quality strained-Si material with a high relaxation degree and ultra-thin SiGe virtual substrate to meet the requirements of device applications.展开更多
An innovative formaldehyde gas sensor based on thin membrane type metal oxide of Ti O2 layer was designed and fabricated. This sensor under ultraviolet(UV) light emitting diode(LED) illumination exhibits a higher resp...An innovative formaldehyde gas sensor based on thin membrane type metal oxide of Ti O2 layer was designed and fabricated. This sensor under ultraviolet(UV) light emitting diode(LED) illumination exhibits a higher response to formaldehyde than that without UV illumination at low temperature. The sensitivities of the sensor under steady working condition were calculated for different gas concentrations. The sensitivity to formaldehyde of 7.14 mg/m^3 is about 15.91 under UV illumination with response time of 580 s and recovery time of 500 s. The device was fabricated through micro-electro-mechanical system(MEMS) processing technology. First, plasma immersion ion implantation(PIII) was adopted to form black polysilicon, then a nanoscale TiO_2 membrane with thickness of 53 nm was deposited by DC reactive magnetron sputtering to obtain the sensing layer. By such fabrication approaches, the nanoscale polysilicon presents continuous rough surface with thickness of 50 nm, which could improve the porosity of the sensing membrane. The fabrication process can be mass-produced for the MEMS process compatibility.展开更多
基金Project supported by the Funds of the State Key Laboratory of Electronic Thin Films and Integrated Devices,China(No.D0200 401030108KD0022).
文摘In order to fabricate strained-Si MOSFETs,we present a method to prepare strained-Si material with highquality surface and ultra-thin SiGe virtual substrate.By sandwiching a low-temperature Si（LT-Si） layer between a Si buffer and a pseudomorphic Si_（0.8）Ge_（0.2） layer,the surface roughness root mean square（RMS） is 1.02 nm and the defect density is 10~6 cm^（-2） owing to the misfit dislocations restricted to the LT-Si layer and the threading dislocations suppressed from penetrating into the Si_（0.8）Ge_（0.2） layer.By employing P~＋ implantation and rapid thermal annealing, the strain relaxation degree of the Si_（0.8）Ge_（0.2） layer increases from 85.09%to 96.41%and relaxation is more uniform. Meanwhile,the RMS（1.1nm） varies a little and the defect density varies little.According to the results,the method of combining an LT-Si layer with ion implantation can prepare high-quality strained-Si material with a high relaxation degree and ultra-thin SiGe virtual substrate to meet the requirements of device applications.
基金supported by the National Natural Science Foundation of China(Nos.61335008,61274119 and 61306141)the National High Technology Research and Development Program of China(No.2015AA042605)the Natural Science Foundation of Jiangsu Province(No.BK20131099)
文摘An innovative formaldehyde gas sensor based on thin membrane type metal oxide of Ti O2 layer was designed and fabricated. This sensor under ultraviolet(UV) light emitting diode(LED) illumination exhibits a higher response to formaldehyde than that without UV illumination at low temperature. The sensitivities of the sensor under steady working condition were calculated for different gas concentrations. The sensitivity to formaldehyde of 7.14 mg/m^3 is about 15.91 under UV illumination with response time of 580 s and recovery time of 500 s. The device was fabricated through micro-electro-mechanical system(MEMS) processing technology. First, plasma immersion ion implantation(PIII) was adopted to form black polysilicon, then a nanoscale TiO_2 membrane with thickness of 53 nm was deposited by DC reactive magnetron sputtering to obtain the sensing layer. By such fabrication approaches, the nanoscale polysilicon presents continuous rough surface with thickness of 50 nm, which could improve the porosity of the sensing membrane. The fabrication process can be mass-produced for the MEMS process compatibility.
