The degradation mechanism of enhancement-mode Al Ga N/Ga N high electron mobility transistors(HEMTs)fabricated by fluorine plasma ion implantation technology is one major concern of HEMT’s reliability.It is observed ...The degradation mechanism of enhancement-mode Al Ga N/Ga N high electron mobility transistors(HEMTs)fabricated by fluorine plasma ion implantation technology is one major concern of HEMT’s reliability.It is observed that the threshold voltage shows a significant negative shift during the typical long-term on-state gate overdrive stress.The degradation does not originate from the presence of as-grown traps in the Al Ga N barrier layer or the generated traps during fluorine ion implantation process.By comparing the relationships between the shift of threshold voltage and the cumulative injected electrons under different stress conditions,a good agreement is observed.It provides direct experimental evidence to support the impact ionization physical model,in which the degradation of E-mode HEMTs under gate overdrive stress can be explained by the ionization of fluorine ions in the Al Ga N barrier layer by electrons injected from 2DEG channel.Furthermore,our results show that there are few new traps generated in the Al Ga N barrier layer during the gate overdrive stress,and the ionized fluorine ions cannot recapture the electrons.展开更多
The defect distribution across an ultrathin film CdTe layer of a CdS/CdTe solar cell is modelled by solving the balance equation in steady state. The degradation of the device parameters due to the induced defects dur...The defect distribution across an ultrathin film CdTe layer of a CdS/CdTe solar cell is modelled by solving the balance equation in steady state. The degradation of the device parameters due to the induced defects during ion implantation is considered where the degradation rate is accelerated if the defect distribution is considerable.The defect concentration is maximum at the surface of the CdTe layer where implantation is applied and it is minimum at the junction with the CdS layer. It shows that ultrathin devices degrade faster if the defect concentration is high at the junction rather than the back region(CdTe/Metal). Since the front and back contacts of the device are close in ultrathin films and the electric field is strong to drive the defects into the junction, the p-doping process might be precisely controlled during ion implantation. The modeling results presented here are in agreement with the few available experimental reports in literature about the degradation and defect configuration of the ultrathin CdTe films.展开更多
We report the DC and RF characteristics of AlN/GaN high electron mobility transistors(HEMTs) with the gate length of 100 nm on sapphire substrates. The device exhibits a maximum drain current density of 1.29 A/mm and ...We report the DC and RF characteristics of AlN/GaN high electron mobility transistors(HEMTs) with the gate length of 100 nm on sapphire substrates. The device exhibits a maximum drain current density of 1.29 A/mm and a peak transconductance of 440 m S/mm. A current gain cutoff frequency and a maximum oscillation frequency of 119 GHz and 155 GHz have been obtained, respectively. Furthermore, the large signal load pull characteristics of the AlN/GaN HEMTs were measured at 29 GHz. An output power density of 429 m W/mm has been demonstrated at a drain bias of 10 V. To the authors’ best knowledge, this is the earliest demonstration of power density at the Ka band for Al N/Ga N HEMTs in the domestic, and also a high frequency of load-pull measurements for Al N/Ga N HEMTs.展开更多
Higher-κ dielectric LaLuO_3,deposited by molecular beam deposition,with TiN as gate stack is integrated into high-mobility Si/SiGe/SOI quantum-well p-type metal-oxide-semiconductor field effect transistors.Threshold ...Higher-κ dielectric LaLuO_3,deposited by molecular beam deposition,with TiN as gate stack is integrated into high-mobility Si/SiGe/SOI quantum-well p-type metal-oxide-semiconductor field effect transistors.Threshold voltage shift and capacitance equivalent thickness shrink are observed,resulting from oxygen scavenging effect in LaLuO_3 with Ti-rich TiN after high temperature annealing.The mechanism of oxygen scavenging and its potential for resistive memory applications are analyzed and discussed.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61334002,61106106,and 61474091) the Opening Project of Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory(Grant No.ZHD201206)+1 种基金 the New Experiment Development Funds for Xidian University,China(Grant No.SY1213) the Scientific Research Foundation for the Returned Overseas Chinese Scholars
文摘The degradation mechanism of enhancement-mode Al Ga N/Ga N high electron mobility transistors(HEMTs)fabricated by fluorine plasma ion implantation technology is one major concern of HEMT’s reliability.It is observed that the threshold voltage shows a significant negative shift during the typical long-term on-state gate overdrive stress.The degradation does not originate from the presence of as-grown traps in the Al Ga N barrier layer or the generated traps during fluorine ion implantation process.By comparing the relationships between the shift of threshold voltage and the cumulative injected electrons under different stress conditions,a good agreement is observed.It provides direct experimental evidence to support the impact ionization physical model,in which the degradation of E-mode HEMTs under gate overdrive stress can be explained by the ionization of fluorine ions in the Al Ga N barrier layer by electrons injected from 2DEG channel.Furthermore,our results show that there are few new traps generated in the Al Ga N barrier layer during the gate overdrive stress,and the ionized fluorine ions cannot recapture the electrons.
文摘The defect distribution across an ultrathin film CdTe layer of a CdS/CdTe solar cell is modelled by solving the balance equation in steady state. The degradation of the device parameters due to the induced defects during ion implantation is considered where the degradation rate is accelerated if the defect distribution is considerable.The defect concentration is maximum at the surface of the CdTe layer where implantation is applied and it is minimum at the junction with the CdS layer. It shows that ultrathin devices degrade faster if the defect concentration is high at the junction rather than the back region(CdTe/Metal). Since the front and back contacts of the device are close in ultrathin films and the electric field is strong to drive the defects into the junction, the p-doping process might be precisely controlled during ion implantation. The modeling results presented here are in agreement with the few available experimental reports in literature about the degradation and defect configuration of the ultrathin CdTe films.
基金Project supported by the National Natural Science Foundation of China(No.61306113)
文摘We report the DC and RF characteristics of AlN/GaN high electron mobility transistors(HEMTs) with the gate length of 100 nm on sapphire substrates. The device exhibits a maximum drain current density of 1.29 A/mm and a peak transconductance of 440 m S/mm. A current gain cutoff frequency and a maximum oscillation frequency of 119 GHz and 155 GHz have been obtained, respectively. Furthermore, the large signal load pull characteristics of the AlN/GaN HEMTs were measured at 29 GHz. An output power density of 429 m W/mm has been demonstrated at a drain bias of 10 V. To the authors’ best knowledge, this is the earliest demonstration of power density at the Ka band for Al N/Ga N HEMTs in the domestic, and also a high frequency of load-pull measurements for Al N/Ga N HEMTs.
基金Supported by the National Natural Science Foundation of China under Grant No 61306126.
文摘Higher-κ dielectric LaLuO_3,deposited by molecular beam deposition,with TiN as gate stack is integrated into high-mobility Si/SiGe/SOI quantum-well p-type metal-oxide-semiconductor field effect transistors.Threshold voltage shift and capacitance equivalent thickness shrink are observed,resulting from oxygen scavenging effect in LaLuO_3 with Ti-rich TiN after high temperature annealing.The mechanism of oxygen scavenging and its potential for resistive memory applications are analyzed and discussed.