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.     

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.     

High-speed Schottky-barrier pMOSFET with f/sub T/=280 GHz

High-speed results on sub-30-nm gate length pMOSFETs with platinum silicide Schottky-barrier source and drain are reported. With inherently low series resistance and high drive current, these deeply scaled transistors are promising for high-speed analog applications. The fabrication process simplicity is compelling with no implants required. A sub-30-nm gate length pMOSFET exhibited a cutoff frequency of 280 GHz, which is the highest reported to date for a silicon MOS transistor. Off-state leakage current can be easily controlled by augmenting the Schottky barrier height with an optional blanket As implant. Using this approach, good digital performance was also demonstrated.     

Low-power InP/GaAsSb/InP DHBT cascode transimpedance amplifier with GBP/P/sub dc/ of 7.2 GHz/mW

A low-power high gain-bandwidth monolithic cascode transimpedance amplifier using novel InP/GaAsSb/InP DHBT technology was investigated. The amplifier exhibited state-of-the-art performance of 17.3 dB gain, 12 GHz bandwidth, 55 dB/spl Omega/ transimpedance, and a corresponding gain-bandwidth of 6.7 THz/spl Omega/ while consuming only 12.2 mW DC power. It also achieved good gain-bandwidth-product per DC power figure-of-merit (GBP/P/sub dc/) of 7.2 GHz/mW     

A submicrometer 252 GHz f/sub T/ and 283 GHz f/sub MAX/ InP DHBT with reduced C/sub BC/ using selectively implanted buried subcollector (SIBS)

The selectively implanted buried subcollector (SIBS) is a method to decouple the intrinsic and extrinsic C/sub BC/ of InP-based double-heterojunction bipolar transistors (DHBTs). Similar to the selectively implanted collector (SIC) used in Si-based bipolar junction transistors (BJTs) and HBTs, ion implantation is used to create a N+ region in the collector directly under the emitter. By moving the subcollector boundary closer to the BC junction, SIBS allows the intrinsic collector to be thin, reducing /spl tau//sub C/, while simultaneously allowing the extrinsic collector to be thick, reducing C/sub BC/. For a 0.35 /spl times/ 6 /spl mu/m/sup 2/ emitter InP-based DHBT with a SIBS, 6 fF total C/sub BC/ and >6 V BV/sub CBO/ were obtained with a 110-nm intrinsic collector thickness. A maximum f/sub T/ of 252 GHz and f/sub MAX/ of 283 GHz were obtained at a V/sub CE/ of 1.6 V and I/sub C/ of 7.52 mA. Despite ion implantation and materials regrowth during device fabrication, a base and collector current ideality factor of /spl sim/2.0 and /spl sim/1.4, respectively, at an I/sub C/ of 100 /spl mu/A, and a peak dc /spl beta/ of 36 were measured.     

Self-aligned InP DHBT with f/sub /spl tau// and f/sub max/ over 300 GHz in a new manufacturable technology

We report self-aligned indium-phosphide double-heterojunction bipolar transistor devices in a new manufacturable technology with both cutoff frequency (f/sub /spl tau//) and maximum oscillation frequency (f/sub max/) over 300 GHz and open-base breakdown voltage (BV/sub ceo/) over 4 V. Logic circuits fabricated using these devices in a production integrated-circuit process achieved a current-mode logic ring-oscillator gate delay of 1.95 ps and an emitter-coupled logic static-divider frequency of 152 GHz, both of which closely matched model-based circuit simulations.     

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/.     

InP/GaAsSb type-II DHBTs with GaAsSb/lnGaAs superlattice-base and GaAsSb bulk-base structures

High-performance InP/GaAsSb double heteroj unction bipolar transistor (DHBT) employing GaAsSb/lnGaAs superlattice-base structure is demonstrated and compared with GaAsSb bulk-base structure by two-dimensional simulation analysis. The proposed device exhibits a higher current gain of 257 than the conventional InP/GaAsSb type-II DHBT with a lower current gain of 180, attributed to the tynneling behavior of minority carriers in the GaAsSb/lnGaAs superlattice-base region under large forward base—emitter bias. In addition, a larger unity gain cutoff frequency of 19.1 GHz is botained for the superlattice-base device than that of 17.2 GHz for the bulk-base device.     

A 160-GHz f/sub T/ and 140-GHz f/sub MAX/ submicrometer InP DHBT in MBE regrown-emitter technology

We report a 0.7/spl times/8 /spl mu/m/sup 2/ InAlAs-InGaAs-InP double heterojunction bipolar transistor, fabricated in a molecular-beam epitaxy (MBE) regrown-emitter technology, exhibiting 160 GHz f/sub T/ and 140 GHz f/sub MAX/. These initial results are the first known RF results for a nonselective regrown-emitter heterojunction bipolar transistor, and the fastest ever reported using a regrown base-emitter heterojunction. The maximum current density is J/sub E/=8/spl times/10/sup 5/ A/cm/sup 2/ and the collector breakdown voltage V/sub CEO/ is 6 V for a 1500-/spl Aring/ collector. In this technology, the dimension of base-emitter junction has been scaled to an area as low as 0.3/spl times/4 /spl mu/m/sup 2/ while a larger-area extrinsic emitter maintains lower emitter access resistance. Furthermore, the application of a refractory metal (Ti-W) base contact beneath the extrinsic emitter regrowth achieves a fully self-aligned device topology.     

10-GHz power performance of a type II InP/GaAsSb DHBT

Type-II InP/GaAsSb double heterojunction bipolar transistors (DHBTs) were fabricated and microwave power performance was measured. For an InP collector thickness of 150 nm, the DHBTs show a current gain of 24, low offset voltages, and a BV/sub CEO/>6V. The 1.2/spl times/16 /spl mu/m/sup 2/ devices show f/sub T/=205GHz and f/sub MAX/=106GHz at J/sub C/=304 kA/cm/sup 2/. These devices delivered 12.6 dBm to the load at P/sub AVS/=3.3 dBm operating at 10 GHz, yielding a power-added efficiency of 41% and G/sub T/=9.3 dB.     

Self-aligned SiGe NPN transistors with 285 GHz f/sub MAX/ and 207 GHz f/sub T/ in a manufacturable technology

This paper reports on SiGe NPN HBTs with unity gain cutoff frequency (f_T) of 207 GHz and an f_MAX extrapolated from Mason's unilateral gain of 285 GHz. f_MAX extrapolated from maximum available gain is 194 GHz. Transistors sized 0.12×2.5 μm² have these characteristics at a linear current of 1.0 mA/μm (8.3 mA/μm²). Smaller transistors (0.12×0.5 μm²) have an f_T of 180 GHz at 800 μA current. The devices have a pinched base sheet resistance of 2.5 kΩ/sq. and an open-base breakdown voltage BV_CEO of 1.7 V. The improved performance is a result of a new self-aligned device structure that minimizes parasitic resistance and capacitance without affecting f_T at small lateral dimensions     

Diamond FET using high-quality polycrystalline diamond with f/sub T/ of 45 GHz and f/sub max/ of 120 GHz

Using high-quality polycrystalline chemical-vapor-deposited diamond films with large grains (/spl sim/100 /spl mu/m), field effect transistors (FETs) with gate lengths of 0.1 /spl mu/m were fabricated. From the RF characteristics, the maximum transition frequency f/sub T/ and the maximum frequency of oscillation f/sub max/ were /spl sim/ 45 and /spl sim/ 120 GHz, respectively. The f/sub T/ and f/sub max/ values are much higher than the highest values for single-crystalline diamond FETs. The dc characteristics of the FET showed a drain-current density I/sub DS/ of 550 mA/mm at gate-source voltage V/sub GS/ of -3.5 V and a maximum transconductance g/sub m/ of 143 mS/mm at drain voltage V/sub DS/ of -8 V. These results indicate that the high-quality polycrystalline diamond film, whose maximum size is 4 in at present, is a most promising substrate for diamond electronic devices.     

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.     

MOVPE grown InAlAs/InGaAs/InP MODFETs with very high f/sub T/

High-performance 0.15 mu m gate length modulation-doped field-effect transistors (MODFETs) have been fabricated on a lattice-matched InAlAs/InGaAs heterostructure grown by organic vapour phase epitaxy (MOVPE). Excellent 'kink-free' DC characteristics with extrinsic transconductance g/sub m/ of 1080 mS/mm at a drain current of 508 mA/mm have been achieved. A unity current-gain cutoff frequency f/sub T/ of 187 GHz at room temperature has been measured, which is the highest value reported for MOVPE-grown lattice-matched InAlAs/InGaAs MODFETs.<>     

300 GHz InP/GaAsSb/InP double HBTs with high current capability andBVCEO>6 V

We report MOCVD-grown NpN InP/GaAsSb/InP abrupt double heterojunction bipolar transistors (DHBTs) with simultaneous values of f _T and f_MAX as high as 300 GHz for J_C=410 kA/cm² at V_CE=1.8 V. The devices maintain outstanding dynamic performances over a wide range of biases including the saturation mode. In this material system the p+ GaAsSb base conduction band edge lies 0.10-0.15 eV above the InP collector conduction band, thus favoring the use of nongraded base-collector designs without the current blocking effect found in conventional InP/GaInAs-based DHBTs. The 2000 Å InP collector provides good breakdown voltages of BV_CEO=6 V and a small collector signal delay of ~0.23 ps. Thinner 1500 Å collectors allow operation at still higher currents with f_T>200 GHz at J_C=650 kA/cm²     

Submicron InP-InGaAs single heterojunction bipolar transistors with f/sub T/ of 377 GHz

Submicron InP-InGaAs-based single heterojunction bipolar transistors (SHBTs) are fabricated to achieve record-breaking speed performance using an aggressively scaled epitaxial structure coupled with a submicron emitter process. SHBTs with dimensions of 0.35 /spl times/16 /spl mu/m have demonstrated a maximum current gain cutoff frequency f/sub T/ of 377 GHz with a simultaneous maximum power gain cutoff frequency f/sub MAX/ of 230 GHz at the current density Jc of 650 kA/cm/sup 2/. Typical BV/sub CEO/ values exceed 3.7 V.     

High-Current-Gain InP/GaInP/GaAsSb/InP DHBTs With fT = 436 GHz

Combining a pseudomorphically strained (Ga,In)P emitter with a GaAs_0.6Sb_0.4 base effectively eliminates the emitter heterojunction type-II conduction band offset in InP/GaAsSb double heterojunction bipolar transistors (DHBTs). A peak f_T of 436 GHz at J_C = 10 mA/mum², with BV_CEO = 3.8 V, is achieved with 0.6 times 5 mum² InP/GalnP/GaAsSb DHBTs with a 75-nm InP collector. Compared to a binary InP emitter, the (Ga,In)P emitter doubles the DC current gain from 166 to 338 for otherwise identical devices. These are the highest DC current gain and cutoff frequencies to date in uniform base GaAsSb DHBTs. The gain improvement reported here will greatly facilitate device design tradeoffs that are encountered while scaling InP/GaAsSb DHBTs toward higher frequencies by allowing higher base doping levels and smaller emitter geometries.     

AlGaN/GaN HEMTs on SiC with f/sub T/ of over 120 GHz

AlGaN/GaN high electron mobility transistors (HEMTs) grown on semi-insulating SiC substrates with a 0.12 /spl mu/m gate length have been fabricated. These 0.12-/spl mu/m gate-length devices exhibited maximum drain current density as high as 1.23 A/mm and peak extrinsic transconductance of 314 mS/mm. The threshold voltage was -5.2 V. A unity current gain cutoff frequency (f/sub T/) of 121 GHz and maximum frequency of oscillation (f/sub max/) of 162 GHz were measured on these devices. These f/sub T/ and f/sub max/ values are the highest ever reported values for GaN-based HEMTs.     

GaInAs/InP DHBT incorporating thick extrinsic base and selectivelyregrown emitter

A novel approach for realising a double heterojunction bipolar transistor (DHRT) with a low base resistance, which incorporates a thick extrinsic base and a regrown emitter is proposed and demonstrated. A combination of selective MOVPE regrowth and selective wet chemical etching resulted in a new self-aligned DHBT structure. Fabricated microwave transistors exhibited good DC and microwave characteristics