Good Output Characteristics Research Articles

Gate oxideprepared by nanometre silicon wet oxidation at low temperature for Si/SiGe PMOSFET application

A high-quality thin gate oxidefor application in Si/SiGe heterostructure PMOSFETs is prepared bynanometre silicon wet oxidation at 750 °C by taking full advantage of the peculiar phase in polysilicon thermal oxidation. Thecombination of low temperature and a short processing time prevents strain relaxation and Ge outdiffusion in the compressivelystrained SiGe channel. Its structural stability and interfacequality are studied by x-ray double-crystal diffraction.Results of C-V characteristics and breakdown measurementsindicate that the gate oxide exhibits a low fixed oxide charge density and a high dielectric breakdown field. Employing this gateoxide, Si/SiGe PMOSFETs with good output characteristics havebeen successfully fabricated.

Technology for the fabrication of ultrashort channel metal–oxide–semiconductor field-effect transistors

We present the experimental details for the preparation of an ultrashort channel metal–oxide–semiconductor field-effect transistor (MOSFET) using a V-groove approach. This new fabrication process allows a definition of the channel with a resolution that exceeds the limit of the lithography used. The approach is based on the combination of electron beam lithography and anisotropic etching of an epitaxial silicon layered structure based on ultrathin silicon on insulator (SOI). A self-limiting etching process forms a “V” shaped groove into the silicon stack and the region at the tip of the V groove becomes the channel. The definition of the channel can be as small as 10 nm in length but it depends strongly on the anisotropic etching behavior, the quality of the molecular beam epitaxy grown layers, and the definition of the mask formed by the lithography. Here we discuss the fabrication of V-groove openings with the appropriate dimensions and quality required to fabricate nanoscale devices. The control of the V-groove process is discussed for making MOSFETs with good output characteristics.

Scheme for the fabrication of ultrashort channel metal-oxide-semiconductor field-effect transistors

We present a scheme for the fabrication of ultrashort channel length metal-oxide-semiconductor field-effect transistors (MOSFETs) involving nanolithography and molecular-beam epitaxy. The active channel is undoped and is defined by a combination of nanometer-scale patterning and anisotropic etching of an n++ layer grown on a silicon on insulator wafer. The method is self-limiting and can produce MOSFET devices with channel lengths of less than 10 nm. Measurements on the first batch of n-MOSFET devices fabricated with this approach show very good output characteristics and good control of short-channel effects.

Refractory WNx/W Self-Aligned Gate GaAs Power Metal-Semiconductor Field-Effect Transistor for 1.9-GHz Digital Mobile Communication System Operating with a Single Low-Voltage Supply

We have developed a refractory WNx /W self-aligned gate GaAs power metal-semiconductor field-effect transistor (MESFET) for use in L-band digital mobile communication systems. This power MESFET operates with high efficiency and low distortion at a gate bias of 0 V and a low drain bias of 2.7 V, because of its small drain knee voltage, high transconductance and sufficient breakdown voltage. This power MESFET is quite promising for a highly efficient linear power amplifier IC operating with a single low-voltage supply. Good output characteristics of the power MESFET with 1 mm gate width were attained for π/4-shifted quadrature phase shift keying (QPSK) modulated input signals in the 1.9-GHz band, such as an output power of 18.4 dBm, a power gain of 19.0 dB and a high power-added efficiency of 26.4% when a sufficiently low adjacent channel leakage power of -58 dBc was obtained.

Growth and metallization of AlGaAs/GaAs carbon-doped HBTs using trimethylamine alane by CBE

It is shown that the entire structure of high-quality AlGaAs/GaAs heterojunction bipolar transistors (HBTs) including a nonalloyed delta -doped ohmic contact and in-situ Al metallization can be grown by chemical beam epitaxy (CBE) using a new precursor, trimethylamine alane, as the Al source. The graded Al/sub x/Ga/sub 1-x/As and uniform GaAs bases (both approximately 1000 A thick) are doped with carbon to high 10/sup 19/ cm/sup -3/ using trimethyl-Ga. A current gain of 10 at a current density of 2500 A/cm/sup 2/ is obtained for both uniform- and graded-base HBTs. Both devices show good output characteristics.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

GaAs/AlGaAs HEMT structures with multiquantum well channels

The DC performance of 1 mu m gate length HEMTs with three parallel conducting GaAs quantum wells is presented. By variation of the gate voltage the three channels can be switched on successively, leading to three separate peaks in the device transconductance. By optimising the depth of the gate recess the authors fabricated transistors which exhibit good output characteristics and extremely high maximum drain currents of up to 1100 mA/mm.

Planar AlGaAs/GaAs HBT fabricated by MOCVD overgrowth with a grown base

A planar heterojunction bipolar transistor (HBT) with an AlGaAs emitter layer epitaxially grown onto a selectively defined grown base layer, where the base is grown with the collector as part of the original epi, is discussed. The transistors fabricated with this process exhibit good gain and output characteristics. Transistors with 7*7 mu m/sup 2/ emitters have exhibited a DC current gain of 10 to 1000 for base doping from 1*10/sup 19/ to 8*10/sup 17/ cm/sup 3/, respectively, and Early voltages >or=100 V. The propagation delay of 19-stage ring oscillators was 87 ps/gate. The transistor-fabrication process was designed to be manufacturable, and the planar nature of the transistor surface should permit large-scale integration with good yields.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Characteristics of S-VHS tape

Improvements in the performance of oxide tape used for video tape recorders are discussed. The improvement was mainly attained by the reduction of magnetic particle size to induce high remanent magnetization and low noise. The particle size was reduced to about one-half, and carrier output to noise ratio was substantially increased. In the case of S-VHS tape, the particle size was further reduced and tape coercivity (H/sub c/) was slightly increased so that its performance was improved. In spite of higher H/sub c/, the optimum recording current is not far from that of VHS tape, and S-VHS tape shows good output characteristics. Thus, recording is adequately performed with a ferrite head. Th characteristics of S-VHS tape are described and compared with those of metal powder tape. >

Field effect transistor microwave characterization: noise figure, gain, power measurements on microwave bench: M. Binet and P. Baudet. Acta Electronica23 (2), 127 (1980) (in German)

A novel idea that using dynamic threshold voltage metal-oxide-semiconductor (DTMOS) to suppress the fringing-induced barrier-lowing (FIBL) effect caused by application of high-k gate dielectrics into MOSFET is proposed in this paper. The performance of DTMOS is compared with the conventional MOSFET with high-k gate dielectrics. It is shown that with high-k gate dielectrics introduced into MOSFET, using DTMOS structure can not only retain its good subthreshold and output characteristics resulted from dynamic threshold voltage, but also suppress FIBL effect caused by application of the high-k gate dielectrics and can get better short-channel performance. Devices with different channel doping profile and smaller size are also simulated. Simulated results show that the above mentioned advantages are still remained.