电流增益截止频率为441 GHz的InGaAs/InAlAs InP HEMT

本文设计并制作了fT>400 GHz的In_(0.53)Ga_(0.47)As/In_(0.52)Al_(0.48)As铟磷高电子迁移率晶体管(InP HEMT)。采用窄栅槽技术优化了寄生电阻。器件栅长为54.4 nm,栅宽为2×50μm。最大漏极电流IDS.max为957 mA/mm,最大跨导gm.max为1265 mS/mm。即使在相对较小的VDS=0.7 V下,电流增益截止频率fT达到了441 GHz,最大振荡频率fmax达到了299 GHz。该器件可应用于太赫兹单片集成放大器和其他电路中。

Impact of symmetric gate-recess length on the DC and RF characteristics of InP HEMTs

We fabricated a set of symmetric gate-recess devices with gate length of 70 nm.We kept the source-to-drain spacing(L_(SD))unchanged,and obtained a group of devices with gate-recess length(L_(recess))from 0.4µm to 0.8µm through process improvement.In order to suppress the influence of the kink effect,we have done SiN_(X) passivation treatment.The maximum saturation current density(ID_(max))and maximum transconductance(g_(m,max))increase as L_(recess) decreases to 0.4µm.At this time,the device shows ID_(max)=749.6 mA/mm at V_(GS)=0.2 V,V_(DS)=1.5 V,and g_(m,max)=1111 mS/mm at V_(GS)=−0.35 V,V_(DS)=1.5 V.Meanwhile,as L_(recess) increases,it causes parasitic capacitance C_(gd) and g_(d) to decrease,making f_(max) drastically increases.When L_(recess)=0.8µm,the device shows f_(T)=188 GHz and f_(max)=1112 GHz.

Heterogeneous integration of InP HEMTs on quartz wafer using BCB bonding technology

Heterogeneous integrated InP high electron mobility transistors(HEMTs)on quartz wafers are fabricated successfully by using a reverse-grown InP epitaxial structure and benzocyclobutene(BCB)bonding technology.The channel of the new device is In_(0.7)Ga_(0.3)As,and the gate length is 100 nm.A maximum extrinsic transconductance gm,max of 855.5 mS/mm and a maximum drain current of 536.5 mA/mm are obtained.The current gain cutoff frequency is as high as 262 GHz and the maximum oscillation frequency reaches 288 GHz.In addition,a small signal equivalent circuit model of heterogeneous integration of InP HEMTs on quartz wafer is built to characterize device performance.

Impact of gate offset in gate recess on DC and RF performance of InAlAs/InGaAs InP-based HEMTs

A set of 100-nm gate-length In P-based high electron mobility transistors(HEMTs)were designed and fabricated with different gate offsets in gate recess.A novel technology was proposed for independent definition of gate recess and T-shaped gate by electron beam lithography.DC and RF measurement was conducted.With the gate offset varying from drain side to source side,the maximum drain current(I_(ds,max))and transconductance(g_(m,max))increased.In the meantime,fTdecreased while f;increased,and the highest fmax of 1096 GHz was obtained.It can be explained by the increase of gate-source capacitance and the decrease of gate-drain capacitance and source resistance.Output conductance was also suppressed by gate offset toward source side.This provides simple and flexible device parameter selection for HEMTs of different usages.

Enhancement of fMAX of InP-based HEMTs by double-recessed offset gate process

A double-recessed offset gate process technology for In P-based high electron mobility transistors(HEMTs)has been developed in this paper.Single-recessed and double-recessed HEMTs with different gate offsets have been fabricated and characterized.Compared with single-recessed devices,the maximum drain-source current(I_(D,max))and maximum extrinsic transconductance(g_(m,max))of double-recessed devices decreased due to the increase in series resistances.However,in terms of RF performance,double-recessed HEMTs achieved higher maximum oscillation frequency(f_(MAX))by reducing drain output conductance(g_(m,max))and drain to gate capacitance(C_gd).In addition,further improvement of fMAXwas observed by adjusting the gate offset of double-recessed devices.This can be explained by suppressing the ratio of C_(gd)to source to gate capacitance(C_gd)by extending drain-side recess length(Lrd).Compared with the single-recessed HEMTs,the f;of double-recessed offset gate HEMTs was increased by about 20%.