Improved DC and RF performance in Si/SiGe n-MODFETs with ion-implanted buried p-well doping

The dc and RF characteristics of Si/SiGe n-MODFETs with buried p-well doping incorporated by ion implantation are reported. At a drain-to-source biasV/sub ds/ of +1 V devices with 140-nm gate length had peak transconductance g/sub m/ of 450 mS/mm, and maximum dc voltage gain A/sub v/ of 20. These devices also had "off-state" drain current I/sub off/ of 0.15 mA/mm at V/sub g/=-0.5 V. Control devices without p-well doping had A/sub v/=8.1 and I/sub off/=13 mA/mm under the same bias conditions. MODFETs with p-well doping had f/sub T/ as high as 72 GHz at V/sub ds/=+1.2 V. These devices also achieved f/sub T/ of 30 GHz at a drain current, I/sub d/, of only 9.8 mA/mm, compared to I/sub d/=30 mA/mm for previously published MODFETs with no p-well doping and similar peak f/sub T/.     

DC, RF, and microwave noise performances of AlGaN/GaN HEMTs on sapphire substrates

High-performance AlGaN/GaN high electron-mobility transistors with 0.18-/spl mu/m gate length have been fabricated on a sapphire substrate. The devices exhibited an extrinsic transconductance of 212 mS/mm, a unity current gain cutoff frequency (f/sub T/) of 101 GHz, and a maximum oscillation frequency (f/sub MAX/) of 140 GHz. At V/sub ds/=4 V and I/sub ds/=39.4 mA/mm, the devices exhibited a minimum noise figure (NF/sub min/) of 0.48 dB and an associated gain (Ga) of 11.16 dB at 12 GHz. Also, at a fixed drain bias of 4 V with the drain current swept, the lowest NFmin of 0.48 dB at 12 GHz was obtained at I/sub ds/=40 mA/mm, and a peak G/sub a/ of 11.71 dB at 12 GHz was obtained at I/sub ds/=60 mA/mm. With the drain current held at 40 mA/mm and drain bias swept, the NF/sub min/,, increased almost linearly with the increase of drain bias. Meanwhile, the Ga values decreased linearly with the increase of drain bias. At a fixed bias condition (V/sub ds/=4 V and I/sub ds/=40 mA/mm), the NF/sub min/ values at 12 GHz increased from 0.32 dB at -55/spl deg/C to 2.78 dB at 200/spl deg/C. To our knowledge, these data represent the highest f/sub T/ and f/sub MAX/, and the best microwave noise performance of any GaN-based FETs on sapphire substrates ever reported.     

InGaAs-InP mesa DHBTs with simultaneously high f/sub /spl tau// and f/sub max/ and low C/sub cb//I/sub c/ ratio

We report an InP-InGaAs-InP double heterojunction bipolar transistor (DHBT), fabricated using a conventional triple mesa structure, exhibiting a 370-GHz f/sub /spl tau// and 459-GHz f/sub max/, which is to our knowledge the highest f/sub /spl tau// reported for a mesa InP DHBT-as well as the highest simultaneous f/sub /spl tau// and f/sub max/ for any mesa HBT. The collector semiconductor was undercut to reduce the base-collector capacitance, producing a C/sub cb//I/sub c/ ratio of 0.28 ps/V at V/sub cb/=0.5 V. The V/sub BR,CEO/ is 5.6 V and the devices fail thermally only at >18 mW//spl mu/m/sup 2/, allowing dc bias from J/sub e/=4.8 mA//spl mu/m/sup 2/ at V/sub ce/=3.9 V to J/sub e/=12.5 mA//spl mu/m/sup 2/ at V/sub ce/=1.5 V. The device employs a 30 nm carbon-doped InGaAs base with graded base doping, and an InGaAs-InAlAs superlattice grade in the base-collector junction that contributes to a total depleted collector thickness of 150 nm.     

InGaAs/InP DHBTs with 120-nm collector having simultaneously high f/sub /spl tau//, f/sub max//spl ges/450 GHz

InP/In/sub 0.53/Ga/sub 0.47/As/InP double heterojunction bipolar transistors (DHBT) have been designed for increased bandwidth digital and analog circuits, and fabricated using a conventional mesa structure. These devices exhibit a maximum 450 GHz f/sub /spl tau// and 490 GHz f/sub max/, which is the highest simultaneous f/sub /spl tau// and f/sub max/ for any HBT. The devices have been scaled vertically for reduced electron collector transit time and aggressively scaled laterally to minimize the base-collector capacitance associated with thinner collectors. The dc current gain /spl beta/ is /spl ap/ 40 and V/sub BR,CEO/=3.9 V. The devices operate up to 25 mW//spl mu/m/sup 2/ dissipation (failing at J/sub e/=10 mA//spl mu/m/sup 2/, V/sub ce/=2.5 V, /spl Delta/T/sub failure/=301 K) and there is no evidence of current blocking up to J/sub e//spl ges/12 mA//spl mu/m/sup 2/ at V/sub ce/=2.0 V from the base-collector grade. The devices reported here employ a 30-nm highly doped InGaAs base, and a 120-nm collector containing an InGaAs/InAlAs superlattice grade at the base-collector junction.     

InGaAs-InP metamorphic DHBTs grown on GaAs with lattice-matched device performance and f/sub /spl tau//, f/sub max/>268 GHz

InP-In/sub 0.53/Ga/sub 0.47/As-InP double heterojunction bipolar transistors (DHBTs) were grown on a GaAs substrate using a metamorphic buffer layer and then fabricated. The metamorphic buffer layer is InP - employed because of its high thermal conductivity to minimize device heating. An f/sub /spl tau// and f/sub max/ of 268 and 339 GHz were measured, respectively - both records for metamorphic DHBTs. A 70-nm SiO/sub 2/ dielectric sidewall was deposited on the emitter contact to permit a longer InP emitter wet etch for increased device yield and reduced base leakage current. The dc current gain /spl beta/ is /spl ap/35 and V/sub BR,CEO/=5.7 V. The collector leakage current I/sub cbo/ is 90 pA at V/sub cb/=0.3 V. These values of f/sub /spl tau//, f/sub max/, I/sub cbo/, and /spl beta/ are consistent with InP based DHBTs of the same layer structure grown on a lattice-matched InP substrate.     

Al/sub 0.25/Ga/sub 0.75/As/In/sub 0.25/Ga/sub 0.75/As pseudomorphic MODFET with high DC and RF performance

AlGaAs/InGaAs MODFETs having 25% indium in the channel and L/sub G/=0.35 mu m have been fabricated. From DC device characterisation, a maximum saturation current of 670 mA/mm and an extrinsic transconductance of 500 mS/mm have been measured. A maximum unilateral gain cutoff frequency of f/sub c/=205 GHz and a maximum current gain cutoff frequency of f/sub T/=86 GHz have been achieved. Bias dependence of f/sub c/ and f/sub T/ has been measured. At 12 GHz a minimum noise figure of NF=0.8 dB and an associated gain of 11 dB have been measured.<>     

High microwave and noise performance of 0.17-/spl mu/m AlGaN-GaN HEMTs on high-resistivity silicon substrates

AlGaN-GaN high-electron mobility transistors (HEMTs) based on high-resistivity silicon substrate with a 0.17-/spl mu/m T-shape gate length are fabricated. The device exhibits a high drain current density of 550 mA/mm at V/sub GS/=1 V and V/sub DS/=10 V with an intrinsic transconductance (g/sub m/) of 215 mS/mm. A unity current gain cutoff frequency (f/sub t/) of 46 GHz and a maximum oscillation frequency (f/sub max/) of 92 GHz are measured at V/sub DS/=10 V and I/sub DS/=171 mA/mm. The radio-frequency microwave noise performance of the device is obtained at 10 GHz for different drain currents. At V/sub DS/=10 V and I/sub DS/=92 mA/mm, the device exhibits a minimum-noise figure (NF/sub min/) of 1.1 dB and an associated gain (G/sub ass/) of 12 dB. To our knowledge, these results are the best f/sub t/, f/sub max/ and microwave noise performance ever reported on GaN HEMT grown on Silicon substrate.     

15-nm base type-II InP/GaAsSb/InP DHBTs with F/sub T/=384 GHz and a 6-V BV/sub CEO/

Type-II InP/GaAsSb/InP double heterojunction bipolar transistors (DHBTs) with a 15-nm base were fabricated by contact lithography: 0.73/spl times/11 /spl mu/m/sup 2/ emitter devices feature f/sub T/=384GHz (f/sub MAX/=262GHz) and BV/sub CEO/=6V. This is the highest f/sub T/ ever reported for InP/GaAsSb DHBTs, and an "all-technology" record f/sub T//spl times/BV/sub CEO/ product of 2304 GHz/spl middot/V. This result is credited to the favorable scaling of InP/GaAsSb/InP DHBT breakdown voltages (BV/sub CEO/) in thin collector structures.     

High-temperature thermal stability performance in /spl delta/-doped In/sub 0.425/Al/sub 0.575/As--In/sub 0.65/Ga/sub 0.35/As metamorphic HEMT

We report, to our knowledge, the best high-temperature characteristics and thermal stability of a novel /spl delta/-doped In/sub 0.425/Al/sub 0.575/As--In/sub 0.65/Ga/sub 0.35/As--GaAs metamorphic high-electron mobility transistor. High-temperature device characteristics, including extrinsic transconductance (g/sub m/), drain saturation current density (I/sub DSS/), on/off-state breakdown voltages (BV/sub on//BV/sub GD/), turn-on voltage (V/sub on/), and the gate-voltage swing have been extensively investigated for the gate dimensions of 0.65/spl times/200 /spl mu/m/sup 2/. The cutoff frequency (f/sub T/) and maximum oscillation frequency (f/sub max/), at 300 K, are 55.4 and 77.5 GHz at V/sub DS/=2 V, respectively. Moreover, the distinguished positive thermal threshold coefficient (/spl part/V/sub th///spl part/T) is superiorly as low as to 0.45 mV/K.     

InGaAs-InP DHBTs for increased digital IC bandwidth having a 391-GHz f/sub /spl tau// and 505-GHz f/sub max/

InP-In/sub 0.53/Ga/sub 0.47/As-InP double heterojunction bipolar transistors (DHBT) have been designed for use in high bandwidth digital and analog circuits, and fabricated using a conventional mesa structure. These devices exhibit a maximum 391-GHz f/sub /spl tau// and 505-GHz f/sub max/, which is the highest f/sub /spl tau// reported for an InP DHBT-as well as the highest simultaneous f/sub /spl tau// and f/sub max/ for any mesa HBT. The devices have been aggressively scaled laterally for reduced base-collector capacitance C/sub cb/. In addition, the base sheet resistance /spl rho//sub s/ along with the base and emitter contact resistivities /spl rho//sub c/ have been lowered. The dc current gain /spl beta/ is /spl ap/36 and V/sub BR,CEO/=5.1 V. The devices reported here employ a 30-nm highly doped InGaAs base, and a 150-nm collector containing an InGaAs-InAlAs superlattice grade at the base-collector junction. From this device design we also report a 142-GHz static frequency divider (a digital figure of merit for a device technology) fabricated on the same wafer. The divider operation is fully static, operating from f/sub clk/=3 to 142.0 GHz while dissipating /spl ap/800 mW of power in the circuit core. The circuit employs single-buffered emitter coupled logic (ECL) and inductive peaking. A microstrip wiring environment is employed for high interconnect density, and to minimize loss and impedance mismatch at frequencies >100 GHz.     

A novel InGaP/Al/sub x/Ga/sub 1-x/As/GaAs CEHBT

A new and interesting InGaP/Al/sub x/Ga/sub 1-x/As/GaAs composite-emitter heterojunction bipolar transistor (CEHBT) is fabricated and studied. Based on the insertion of a compositionally linear graded Al/sub x/Ga/sub 1-x/As layer, a near-continuous conduction band structure between the InGaP emitter and the GaAs base is developed. Simulation results reveal that a potential spike at the emitter/base heterointerface is completely eliminated. Experimental results show that the CEHBT exhibits good dc performances with dc current gain of 280 and greater than unity at collector current densities of J/sub C/=21kA/cm/sup 2/ and 2.70/spl times/10/sup -5/ A/cm/sup 2/, respectively. A small collector/emitter offset voltage /spl Delta/V/sub CE/ of 80 meV is also obtained. The studied CEHBT exhibits transistor action under an extremely low collector current density (2.7/spl times/10/sup -5/ A/cm/sup 2/) and useful current gains over nine decades of magnitude of collector current density. In microwave characteristics, the unity current gain cutoff frequency f/sub T/=43.2GHz and the maximum oscillation frequency f/sub max/=35.1GHz are achieved for a 3/spl times/20 /spl mu/m/sup 2/ device. Consequently, the studied device shows promise for low supply voltage and low-power circuit applications.     

AlGaN/GaN MIS-HFETs with f/sub T/ of 163 GHz using cat-CVD SiN gate-insulating and passivation Layers

Al/sub 0.4/Ga/sub 0.6/N/GaN heterostructure field-effect transistors (HFETs) with an AlGaN barrier thickness of 8 nm and a gate length (L/sub G/) of 0.06-0.2 /spl mu/m were fabricated on a sapphire substrate. We employed two novel techniques, which were thin, high-Al-composition AlGaN barrier layers and SiN gate-insulating, passivation layers formed by catalytic chemical vapor deposition, to enhance high-frequency device characteristics by suppressing the short channel effect. The HFETs with L/sub G/=0.06-0.2 /spl mu/m had a maximum drain current density of 1.17-1.24 A/mm at a gate bias of +1.0 V and a peak extrinsic transconductance of 305-417 mS/mm. The current-gain cutoff frequency (f/sub T/) was 163 GHz, which is the highest value to have been reported for GaN HFETs. The maximum oscillation frequency (f/sub max/) was also high, and its value derived from the maximum stable gain or unilateral gain was 192 or 163 GHz, respectively.     

InAlAs/InGaAs HBTs with simultaneously high values of F/sub /spl tau// and F/sub max/ for mixed analog/digital applications

We report the design, fabrication, and measurement of InAlAs/InGaAs heterostructure bipolar transistors (HBTs) designed for high speed digital circuits. At 0.96 V V/sub CE/ the current gain cutoff frequency, f/sub /spl tau//, is 300 GHz and the maximum frequency of oscillation, f/sub max/, is 235 GHz. This value of f/sub /spl tau//, is the highest reported for bipolar transistors. At a slightly higher V/sub CE/ bias, a high value of 295 GHz for f/sub /spl tau// and f/sub max/ were obtained simultaneously.     

Over 300 GHz f/sub T/ and f/sub max/ InP/InGaAs double heterojunction bipolar transistors with a thin pseudomorphic base

Describes 150-nm-thick collector InP-based double heterojunction bipolar transistors with two types of thin pseudomorphic bases for achieving high f/sub T/ and f/sub max/. The collector current blocking is suppressed by the compositionally step-graded collector structure even at J/sub C/ of over 1000 kA/cm/sup 2/ with practical breakdown characteristics. An HBT with a 20-nm-thick base achieves a record f/sub T/ of 351 GHz at high J/sub C/ of 667 kA/cm/sup 2/, and a 30-nm-base HBT achieves a high value of 329 GHz for both f/sub T/ and f/sub max/. An equivalent circuit analysis suggests that the extremely small carrier-transit-delay contributes to the ultrahigh f/sub T/.     

High breakdown voltage (Al/sub 0.3/Ga/sub 0.7/)/sub 0.5/In/sub 0.5/P/InGaAs quasi-enhancement-mode pHEMT with field-plate technology

A high breakdown voltage and a high turn-on voltage (Al/sub 0.3/Ga/sub 0.7/)/sub 0.5/In/sub 0.5/P/InGaAs quasi-enhancement-mode (E-mode) pseudomorphic HEMT (pHEMTs) with field-plate (FP) process is reported for the first time. Between gate and drain terminal, the transistor has a FP metal of 1 /spl mu/m, which is connected to a source terminal. The fabricated 0.5/spl times/150 /spl mu/m/sup 2/ device can be operated with gate voltage up to 1.6 V owing to its high Schottky turn-on voltage (V/sub ON/=0.85 V), which corresponds to a high drain-to-source current (I/sub ds/) of 420 mA/mm when drain-to-source voltage (V/sub ds/) is 3.5 V. By adopting the FP technology and large barrier height (Al/sub 0.3/Ga/sub 0.7/)/sub 0.5/In/sub 0.5/P layer design, the device achieved a high breakdown voltage of -47 V. The measured maximum transconductance, current gain cutoff frequency and maximum oscillation frequency are 370 mS/mm, 22 GHz , and 85 GHz, respectively. Under 5.2-GHz operation, a 15.2 dBm (220 mW/mm) and a 17.8 dBm (405 mW/mm) saturated output power can be achieved when drain voltage are 3.5 and 20 V. These characteristics demonstrate that the field-plated (Al/sub 0.3/Ga/sub 0.7/)/sub 0.5/In/sub 0.5/P E-mode pHEMTs have great potential for microwave power device applications.     

547-GHz f/sub t/ In/sub 0.7/Ga/sub 0.3/As-In/sub 0.52/Al/sub 0.48/As HEMTs with reduced source and drain resistance

We fabricated 30-nm gate pseudomorphic channel In/sub 0.7/Ga/sub 0.3/As-In/sub 0.52/Al/sub 0.48/As high electron mobility transistors (HEMTs) with reduced source and drain parasitic resistances. A multilayer cap structure consisting of Si highly doped n/sup +/-InGaAs and n/sup +/-InP layers was used to reduce these resistances while enabling reproducible 30-nm gate process. The HEMTs also had a laterally scaled gate-recess that effectively enhanced electron velocity, and an adequately long gate-channel distance of 12nm to suppress gate leakage current. The transconductance (g/sub m/) reached 1.5 S/mm, and the off-state breakdown voltage (BV/sub gd/) defined at a gate current of -1 mA/mm was -3.0 V. An extremely high current gain cutoff frequency (f/sub t/) of 547 GHz and a simultaneous maximum oscillation frequency (f/sub max/) of 400 GHz were achieved: the best performance yet reported for any transistor.     

A 183 GHz f/sub T/ and 165 GHz f/sub max/ regrown-emitter DHBT with abrupt InP emitter

Small-area regrown emitter-base junction InP/In-GaAs/InP double heterojunction bipolar transistors (DHBT) using an abrupt InP emitter are presented for the first time. In a device with emitter-base junction area of 0.7 /spl times/ 8 /spl mu/m/sup 2/, a maximum 183 GHz f/sub T/ and 165 GHz f/sub max/ are exhibited. To our knowledge, this is the highest reported bandwidth for a III-V bipolar transistor utilizing emitter regrowth. The emitter current density is 6/spl times/10/sup 5/ A/cm/sup 2/ at V/sub CE,sat/ = 1.5 V. The small-signal current gain h/sub 21/ = 17, while collector breakdown voltage is near 6 V for the 1500-/spl Aring/-thick collector. The emitter structure, created by nonselective molecular beam epitaxy regrowth, combines a small-area emitter-base junction and a larger-area extrinsic emitter contact, and is similar in structure to that of a SiGe HBT. The higher f/sub T/ and f/sub max/ compared to previously reported devices are achieved by simplified regrowth using an InP emitter and by improvements to the regrowth surface preparation process.     

Low-K/Cu CMOS-based SoC technology with 115-GHz f/sub T/, 100-GHz f/sub max/, low noise 80-nm RF CMOS, high-Q MiM capacitor, and spiral Cu inductor

Logic CMOS-based RF technology is introduced for a 10-Gb transceiver in which active and passive RF devices have been realized in a single chip. RF nMOS of 115-GHz f/sub T/, 100-GHz f/sub max/, and sub-1.0-dB NF/sub min/ at 10 GHz have been fabricated by aggressive device scaling and layout optimization. High-Q MiM capacitor and spiral Cu inductors have been successfully implemented in the same chip by 0.13-/spl mu/m low-K/Cu back end of integration line technology. Core 1.0 V MOS and/or junction varactors for VCO at 10 GHz are offerings free of extra cost and realized by the elaborated layout.     

High-responsivity high-gain In/sub 0.53/Ga/sub 0.47/As-InP quantum-well infrared photodetectors grown using metal-organic vapor phase epitaxy

We report the growth and fabrication of bound-to-bound In/sub 0.53/Ga/sub 0.47/As-InP quantum-well infrared photodetectors using metal-organic vapor phase epitaxy. These detectors have a peak detection wavelength of 8.5 /spl mu/m. The peak responsivities are extremely large with R/sub pk/=6.9 A/W at bias voltage V/sub b/=3.4 V and temperature T=10 K. These large responsivities arise from large detector gain that was found to be g/sub n/=82 at V/sub b/=3.8 V from dark current noise measurements at T=77 K and g/sub p/=18.4 at V/sub b/=3.4 V from photoresponse data at T=10 K. The background-limited temperature with F/1.2 optics is T/sub BLIP/=65 K for 0相似文献   

DC and RF characteristics of E-mode Ga/sub 0.51/In/sub 0.49/P-In/sub 0.15/Ga/sub 0.85/As pseudomorphic HEMTs

The DC and RF characteristics of Ga/sub 0.49/In/sub 0.51/P-In/sub 0.15/Ga/sub 0.85/As enhancement- mode pseudomorphic HEMTs (pHEMTs) are reported for the first time. The transistor has a gate length of 0.8 /spl mu/m and a gate width of 200 /spl mu/m. It is found that the device can be operated with gate voltage up to 1.6 V, which corresponds to a high drain-source current (I/sub DS/) of 340 mA/mm when the drain-source voltage (V/sub DS/) is 4.0 V. The measured maximum transconductance, current gain cut-off frequency, and maximum oscillation frequency are 255.2 mS/mm, 20.6 GHz, and 40 GHz, respectively. When this device is operated at 1.9 GHz under class-AB bias condition, a 14.7-dBm (148.6 mW/mm) saturated power with a power-added efficiency of 50% is achieved when the drain voltage is 3.5 V. The measured F/sub min/ is 0.74 dB under I/sub DS/=15 mA and V/sub DS/=2 V.