With the rapid advancement of 5G communication technology,increasingly stringent demands are placed on the performance and functionality of phase change switches.Given that RF and microwave signals exhibit characteris...With the rapid advancement of 5G communication technology,increasingly stringent demands are placed on the performance and functionality of phase change switches.Given that RF and microwave signals exhibit characteristics of high frequency,high speed,and high precision,it is imperative for phase change switches to possess fast,accurate,and reliable switching capabilities.Moreover,wafer-level compositional homogeneity and resistivity uniformity during semiconductor manufacturing are crucial for ensuring the yield and reliability of RF switches.By controlling magnetron sputter of GeTe through from four key parameters(pressure,power,Ar flow,and post-annealing)and incorporating elemental proportional compensation in the target,we achieved effective modulation over GeTe uniformity.Finally,we successfully demonstrated the process integration of GeTe phase-change RF switches on 6-inch scaled wafers.展开更多
Chalcogenide superlattices Sb_(2)Te_(3)-GeTe is a candidate for interfacial phase-change memory(iPCM) data storage devices.By employing terahertz emission spectroscopy and the transient reflectance spectroscopy togeth...Chalcogenide superlattices Sb_(2)Te_(3)-GeTe is a candidate for interfacial phase-change memory(iPCM) data storage devices.By employing terahertz emission spectroscopy and the transient reflectance spectroscopy together,we investigate the ultrafast photoexcited carrier dynamics and current transients in Sb_(2)Te_(3)-GeTe superlattices.Sample orientation and excitation polarization dependences of the THz emission confirm that ultrafast thermo-electric,shift and injection currents contribute to the THz generation in Sb_(2)Te_(3)-GeTe superlattices.By decreasing the thickness and increasing the number of GeTe and Sb_(2)Te_(3) layer,the interlayer coupling can be enhanced,which significantly reduces the contribution from circular photo-galvanic effect(CPGE).A photo-induced bleaching in the transient reflectance spectroscopy probed in the range of~1100 nm to~1400 nm further demonstrates a gapped state resulting from the interlayer coupling.These demonstrates play an important role in the development of iPCM-based high-speed optoelectronic devices.展开更多
TheⅣ-Ⅵcompound GeTe is considered as a promising alternative to the toxic PbTe for high-efficiency mid-temperature thermoelectric applications.However,pristine GeTe suffers from a high concentration of Ge vacancies,...TheⅣ-Ⅵcompound GeTe is considered as a promising alternative to the toxic PbTe for high-efficiency mid-temperature thermoelectric applications.However,pristine GeTe suffers from a high concentration of Ge vacancies,resulting in an excessively high hole concentration(>1×10^(21)cm^(-3)),which greatly limits its thermoelectric enhancement.To address this issue,CuBiTe_(2)alloying is introduced to increase the formation energy of Ge vacancies in GeTe,thereby inhibiting the high carrier concentration.The carrier scattering caused by the electronegativity difference between different elements is suppressed due to the similar electronegativity of Cu and Ge atoms.A relatively high hole mobility is obtained,which ultimately leads to a high power factor.Additionally,by introducing Se as an alloying element at the anionic site in GeTe,dense point defects with mass/strainfield fluctuations are induced.This contributes to the strengthening of phonon scattering,thereby reducing the lattice thermal conductivity from 1.44 W·m^(-1)·K^(-1)for pristine GeTe to 0.28 W·m^(-1)·K^(-1)for Ge_(0.95)Cu_(0.05)Bi_(0.05)Te_(0.9)Se_(0.15)compound at 623 K.展开更多
GeTe is an excellent mid-temperature thermoelectric material with high dimensionless figure of merit(ZT)values at temperatures over 600 K.Its near-room-temperature performance is less studied due to the intrinsic high...GeTe is an excellent mid-temperature thermoelectric material with high dimensionless figure of merit(ZT)values at temperatures over 600 K.Its near-room-temperature performance is less studied due to the intrinsic high carrier concentration.Here,we successfully enhance the Seebeck coefficient of GeTe from~30 to 220μV·K^(−1) at 300 K,which is achieved by AgInSe2 alloying and Bi doping.It is demonstrated that Bi doping helps to optimize the Seebeck coefficient without deteriorating the intrinsic electrical transport properties of the matrix.A high room-temperature power factor(PF)of~11μW·cm^(−1)·K^(−2) is achieved for a wide range of Bi-doped samples.The simultaneously introduced abundant point defects cause mass and strain fluctuations,which decrease the lattice thermal conductivity(κ_(L))to a low value of 0.6 W·m^(−1)·K^(−1) at 300 K.Due to the synergetic effects of Bi doping in AgInSe2-alloyed GeTe,a high room-temperature ZT value of 0.46 is obtained together with a high ZT value of 1.1 at 523 K.展开更多
基金supported by the National Natural Science Foundation of China(General Program,No.52473331).
文摘With the rapid advancement of 5G communication technology,increasingly stringent demands are placed on the performance and functionality of phase change switches.Given that RF and microwave signals exhibit characteristics of high frequency,high speed,and high precision,it is imperative for phase change switches to possess fast,accurate,and reliable switching capabilities.Moreover,wafer-level compositional homogeneity and resistivity uniformity during semiconductor manufacturing are crucial for ensuring the yield and reliability of RF switches.By controlling magnetron sputter of GeTe through from four key parameters(pressure,power,Ar flow,and post-annealing)and incorporating elemental proportional compensation in the target,we achieved effective modulation over GeTe uniformity.Finally,we successfully demonstrated the process integration of GeTe phase-change RF switches on 6-inch scaled wafers.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2023YFF0719200 and 2022YFA1404004)the National Natural Science Foundation of China(Grant Nos.62322115,61988102,61975110,62335012,and 12074248)+3 种基金111 Project(Grant No.D18014)the Key Project supported by Science and Technology Commission Shanghai Municipality(Grant No.YDZX20193100004960)Science and Technology Commission of Shanghai Municipality(Grant Nos.22JC1400200 and 21S31907400)General Administration of Customs People’s Republic of China(Grant No.2019HK006)。
文摘Chalcogenide superlattices Sb_(2)Te_(3)-GeTe is a candidate for interfacial phase-change memory(iPCM) data storage devices.By employing terahertz emission spectroscopy and the transient reflectance spectroscopy together,we investigate the ultrafast photoexcited carrier dynamics and current transients in Sb_(2)Te_(3)-GeTe superlattices.Sample orientation and excitation polarization dependences of the THz emission confirm that ultrafast thermo-electric,shift and injection currents contribute to the THz generation in Sb_(2)Te_(3)-GeTe superlattices.By decreasing the thickness and increasing the number of GeTe and Sb_(2)Te_(3) layer,the interlayer coupling can be enhanced,which significantly reduces the contribution from circular photo-galvanic effect(CPGE).A photo-induced bleaching in the transient reflectance spectroscopy probed in the range of~1100 nm to~1400 nm further demonstrates a gapped state resulting from the interlayer coupling.These demonstrates play an important role in the development of iPCM-based high-speed optoelectronic devices.
基金financially supported by the National Key Research and Development Program of China(No.2018YFA0702100)National Natural Science Foundation of China(No.U21A2054)the support from Key Discipline of Materials Science and Engineering,Bureau of Education of Guangzhou(No.202255464)。
文摘TheⅣ-Ⅵcompound GeTe is considered as a promising alternative to the toxic PbTe for high-efficiency mid-temperature thermoelectric applications.However,pristine GeTe suffers from a high concentration of Ge vacancies,resulting in an excessively high hole concentration(>1×10^(21)cm^(-3)),which greatly limits its thermoelectric enhancement.To address this issue,CuBiTe_(2)alloying is introduced to increase the formation energy of Ge vacancies in GeTe,thereby inhibiting the high carrier concentration.The carrier scattering caused by the electronegativity difference between different elements is suppressed due to the similar electronegativity of Cu and Ge atoms.A relatively high hole mobility is obtained,which ultimately leads to a high power factor.Additionally,by introducing Se as an alloying element at the anionic site in GeTe,dense point defects with mass/strainfield fluctuations are induced.This contributes to the strengthening of phonon scattering,thereby reducing the lattice thermal conductivity from 1.44 W·m^(-1)·K^(-1)for pristine GeTe to 0.28 W·m^(-1)·K^(-1)for Ge_(0.95)Cu_(0.05)Bi_(0.05)Te_(0.9)Se_(0.15)compound at 623 K.
基金financially supported by the Singapore MOE AcRF Tier 2(Nos.2018-T2-1-010)Singapore A*STAR project(A19D9a0096 and SC25/21-102419)+3 种基金Singapore MOE Tier 1 RG128/21.Q.Zhu and A.Suwardi acknowledge Agency for Science,Technology and Research(A*STAR)Singapore Career Development Fund(CDF)(No.C210112022)the Sustainable Hybrid Lighting System for Controlled Environment Agriculture Program(No.A19D9a0096)support from S&T Program of Hebei(No.206Z4403G)。
文摘GeTe is an excellent mid-temperature thermoelectric material with high dimensionless figure of merit(ZT)values at temperatures over 600 K.Its near-room-temperature performance is less studied due to the intrinsic high carrier concentration.Here,we successfully enhance the Seebeck coefficient of GeTe from~30 to 220μV·K^(−1) at 300 K,which is achieved by AgInSe2 alloying and Bi doping.It is demonstrated that Bi doping helps to optimize the Seebeck coefficient without deteriorating the intrinsic electrical transport properties of the matrix.A high room-temperature power factor(PF)of~11μW·cm^(−1)·K^(−2) is achieved for a wide range of Bi-doped samples.The simultaneously introduced abundant point defects cause mass and strain fluctuations,which decrease the lattice thermal conductivity(κ_(L))to a low value of 0.6 W·m^(−1)·K^(−1) at 300 K.Due to the synergetic effects of Bi doping in AgInSe2-alloyed GeTe,a high room-temperature ZT value of 0.46 is obtained together with a high ZT value of 1.1 at 523 K.
