The Ti/Pt/Au metallization system has an advantage of resisting KOH or TMAH solution etching. To form a good ohmic contact, the Ti/Pt/Au metallization system must be alloyed at 400℃. However, the process temperatures...The Ti/Pt/Au metallization system has an advantage of resisting KOH or TMAH solution etching. To form a good ohmic contact, the Ti/Pt/Au metallization system must be alloyed at 400℃. However, the process temperatures of typical MEMS packaging technologies, such as anodic bonding, glass solder bonding and eutectic bonding, generally exceed 400℃. It is puzzling if the Ti/Pt/Au system is destroyed during the subsequent packaging process. In the present work, the resistance of doped polysilicon resistors contacted by the Ti/Pt/Au metallization system that have undergone different temperatures and time are measured. The experimental results show that the ohmic contacts will be destroyed if heated to 500℃. But if a 20 nm Pt film is sputtered on heavily doped polysilicon and alloyed at 700℃ before sputtering Ti/Pt/Au films, the Pt5 Si2-Ti/Pt/Au metallization system has a higher service temperature of 500℃, which exceeds process temperatures of most typical MEMS packaging technologies.展开更多
1.0μm gate-length GaAs-based MHEMTs have been fabricated by MBE epitaxial material and contact-mode lithography technology. Pt/Ti/Pt/Au and Ti/Pt/Au were evaporated to form gate metals. Excellent DC and RF performanc...1.0μm gate-length GaAs-based MHEMTs have been fabricated by MBE epitaxial material and contact-mode lithography technology. Pt/Ti/Pt/Au and Ti/Pt/Au were evaporated to form gate metals. Excellent DC and RF performances have been obtained, and the transconductance, maximum saturation drain current density, threshold voltage, current cut-off frequency,and maximum oscillation frequency of Pt/Ti/Pt/Au and Ti/Pt/Au MHEMTs were 502 （503） mS/mm, 382（530）mA/mm,0.1（ - 0.5）V,13.4（14.8）GHz,and 17.0（17.5）GHz,respectively. DC-10GHz single-pole double-throw （SPDT） switch MMICs have been designed and fabricated by Ti/Pt/Au MHEMTs. Insertion loss,isolation,input,and out- put return losses of SPDT chips were better than 2.93,23.34,and 20dB.展开更多
A multilayer(Ti/Pt/Cr/Au)resistive temperature sensor was proposed and investigated to precisely measure the temperature characteristic in microfluidic devices.The Ti/Pt/Cr/Au sensor was fabricated by direct current(D...A multilayer(Ti/Pt/Cr/Au)resistive temperature sensor was proposed and investigated to precisely measure the temperature characteristic in microfluidic devices.The Ti/Pt/Cr/Au sensor was fabricated by direct current(DC)sputtering,vacuum evaporation and liftoff process.The thermal annealing test was conducted in the temperature range of 200-800℃for obtaining an appropriate property of the multilayer.Based on the experimental results,400℃was selected as the experimental annealing temperature for the Ti/Pt/Cr/Au layer.The redistribution of structural imperfections and recrystallization promote the density and adhesion of multilayer during the annealing process.With the annealing temperature rising,the annealing process leads to through-thickness migration of chromium and partial depletion of the adhesive layer.The Ti also diffuses into the Pt,which makes the interface disappear.Nevertheless,the layer remains continuous.The temperature coefficient of resistance(TCR)of the sensors was investigated through the microfluidic testing system.The excellent stability and sensitivity of the Ti/Pt/Cr/Au thin-film temperature sensor are verified.Furthermore,the capability of the Ti/Pt/Cr/Au thin-film temperature sensor detecting the sudden temperature change caused by bubble effect is very meaningful to the microfluidic devices.展开更多
基金supported by the National Natural Science Foundation of China(No.61376114)
文摘The Ti/Pt/Au metallization system has an advantage of resisting KOH or TMAH solution etching. To form a good ohmic contact, the Ti/Pt/Au metallization system must be alloyed at 400℃. However, the process temperatures of typical MEMS packaging technologies, such as anodic bonding, glass solder bonding and eutectic bonding, generally exceed 400℃. It is puzzling if the Ti/Pt/Au system is destroyed during the subsequent packaging process. In the present work, the resistance of doped polysilicon resistors contacted by the Ti/Pt/Au metallization system that have undergone different temperatures and time are measured. The experimental results show that the ohmic contacts will be destroyed if heated to 500℃. But if a 20 nm Pt film is sputtered on heavily doped polysilicon and alloyed at 700℃ before sputtering Ti/Pt/Au films, the Pt5 Si2-Ti/Pt/Au metallization system has a higher service temperature of 500℃, which exceeds process temperatures of most typical MEMS packaging technologies.
文摘1.0μm gate-length GaAs-based MHEMTs have been fabricated by MBE epitaxial material and contact-mode lithography technology. Pt/Ti/Pt/Au and Ti/Pt/Au were evaporated to form gate metals. Excellent DC and RF performances have been obtained, and the transconductance, maximum saturation drain current density, threshold voltage, current cut-off frequency,and maximum oscillation frequency of Pt/Ti/Pt/Au and Ti/Pt/Au MHEMTs were 502 （503） mS/mm, 382（530）mA/mm,0.1（ - 0.5）V,13.4（14.8）GHz,and 17.0（17.5）GHz,respectively. DC-10GHz single-pole double-throw （SPDT） switch MMICs have been designed and fabricated by Ti/Pt/Au MHEMTs. Insertion loss,isolation,input,and out- put return losses of SPDT chips were better than 2.93,23.34,and 20dB.
基金financially supported by the National Natural Science Foundation of China(No.51602039)the Central University Support Project(No.ZYGX2016J051)。
文摘A multilayer(Ti/Pt/Cr/Au)resistive temperature sensor was proposed and investigated to precisely measure the temperature characteristic in microfluidic devices.The Ti/Pt/Cr/Au sensor was fabricated by direct current(DC)sputtering,vacuum evaporation and liftoff process.The thermal annealing test was conducted in the temperature range of 200-800℃for obtaining an appropriate property of the multilayer.Based on the experimental results,400℃was selected as the experimental annealing temperature for the Ti/Pt/Cr/Au layer.The redistribution of structural imperfections and recrystallization promote the density and adhesion of multilayer during the annealing process.With the annealing temperature rising,the annealing process leads to through-thickness migration of chromium and partial depletion of the adhesive layer.The Ti also diffuses into the Pt,which makes the interface disappear.Nevertheless,the layer remains continuous.The temperature coefficient of resistance(TCR)of the sensors was investigated through the microfluidic testing system.The excellent stability and sensitivity of the Ti/Pt/Cr/Au thin-film temperature sensor are verified.Furthermore,the capability of the Ti/Pt/Cr/Au thin-film temperature sensor detecting the sudden temperature change caused by bubble effect is very meaningful to the microfluidic devices.
