InP/Al2O3n-channel inversion-mode m.i.s.f.e.t.s using sulphur-diffused source and drain

InP metal-insulator-semiconductor field-effect transistors (m.i.s.f.e.t.s) have been fabricated using c.v.d. Al2O3 as the gate insulator and the sulphur-diffusion process for source and drain. The n-channel inversion-mode device exhibits normally off behaviour. A maximum d.c. transconductance gm of 10 mS (87 mS/mm of gate width) has been obtained.     

Linearization of oscillation frequency for integrated LC-VCO with inversion-mode varactor

Metal-oxide semiconductor (MOS) varactors are widely used in voltage-controlled oscillators (VCOs) due to the need for a tunable capacitance. Two types of varactors that have been integrated on-chip include the inversion-mode and accumulation-mode types. The inversion-mode varactor offers immunity to latch-up, but suffers from a non-linear C(V) characteristic which directly leads to a nonlinear oscillation frequency tuning curve. This paper proposes an oscillation frequency linearization technique for LC-VCO with an inversion-mode varactor. The linearity of the frequency tuning curve is improved by linearization of C(V) characteristics of the inversion-mode varactor. A new varactor configuration consisting of varactor units and resistor divider network is proposed. The single-switch integrated LC-VCO with the proposed varactor configuration is fabricated in TSMC 0.18 μm CMOS technology. The improvement of linearity of the frequency tuning curve has been verified using mathematical models and measurement results.     

Comparison of contact resistance between accumulation-mode and inversion-mode multigate FETs

The performances of accumulation-mode and inversion-mode multigate FETs are compared. The influence of gate underlap on the electrical properties is analyzed. Both simulation results and experimental data show that in a device with gate underlap, accumulation-mode devices have a higher current drive, lower source and drain resistance and less process variability than inversion-mode FETs.     

薄膜积累型SOI pMOSFET

对薄膜积累型SOI pMOSFET的制备和特性进行了研究.把一些特性和反掺杂型SOI pMOSFET进行了比较.其亚阈值斜率只有69mV/decade,而且几乎没有DIBL效应.漏击穿电压为10.5V,与反掺杂型相比,提高了40%.饱和电流为130μA/μm,比反掺杂型提高了27%以上.在3V工作电压下,101级SOI CMOS环形振荡器的单级门延迟为56ps.     

Enhancement-mode GaAs m.o.s.f.e.t. on semi-insulating substrate using a self-aligned gate technique

A self-aligned gate notched channel GaAs m.o.s.f.e.t. structure on semi-insulating substrate is presented. Device operation is mainly in enhancement mode. The transconductance is comparable to enhancement-mode m.e.s.f.e.t.s, j.f.e.t.s and s.i.g.f.e.t.s; however, the output-current capability is essentially increased.     

U.H.F. low-noise GaAs m.e.s.f.e.t. amplifier for colour t.v. broadcasting translator

Low-noise amplifiers for u.h.f. colour t.v. broadcasting translator use have been successfully developed by using 1 ?m gate GaAs m.e.s.f.e.t.s. The obtained performances revealed that a GaAs m.e.s.f.e.t. has low-noise and low intermodulation distortion characteristics, even in the 500?800 MHz frequency range, compared with a Si bipolar transistor.     

Circuit model for the GaAs m.e.s.f.e.t. valid to 12 GHz

A new equivalent circuit is given for the GaAs m.e.s.f.e.t., which includes resistive loss in the feed back elements. The circuit values are given for several 1 ?m-gate GaAs m.e.s.f.e.t.s. A method for fitting s12 to the measured data is described. Finally, the gain and stability factor of several GaAs m.e.s.f.e.t.s. are extrapolated to 24 GHz from the present model.     

Low-noise microwave f.e.t.s fabricated by molecular-beam epitaxy

The growth of m.b.e. GaAs suitable for f.e.t. fabrication is reported. The m.b.e. structure consists of an n+ = 2.5×1018 cm?3 contact layer on top of an n+ = 3.5×1017 cm?3 active layer. Using this material, f.e.t.s. have been fabricated that have a minimum noise figure of 1.5 dB with an associated gain of 15 dB at 8 GHz. These are the best results yet reported for low-noise m.b.e. GaAs f.e.t.s.     

Experiments on integrated gallium-arsenide f.e.t. oscillators at X band

Experimental results obtained with GaAs f.e.t. oscillators at X band are described. It is demonstrated that the output power of f.e.t. oscillators is sufficient to drive X band mixers. The noise measure of these oscillators is competitive with Gunn devices, and can be reduced further.     

Experimental demonstration and analysis of high performance and low 1/f noise Tri-gate MOSFETs by optimizing device structure

In this paper, we experimentally investigate the performance of multi-gate MOSFETs (MUGFETs) using the advanced radical gate oxide and the accumulation-mode (AM) FD-SOI MOSFETs. Firstly, we experimentally demonstrate that the drain current in AM multi-gate MOSFET is improved about 1.3 times compared with conventional inversion-mode (IM) MOSFETs with the same gate oxide. Secondly, we indicate that 1/f noise levels in AM MUGFETs are obviously suppressed compared with the conventional IM MUGFETs. The advantages resulted from the AM device structure for MUGFETs are demonstrated in this experiment.     

Effects of capacitance at crossover wirings in power GaAs m.e.s.f.e.t.s.

Power GaAs f.e.t.s. with an air-bridge crossover were compared with those of SiO2 crossover to find the effect of the capacitance at the crossover points. The capacitance of SiO2 crossover points is much smaller than that of the gate pad or the gate busbar in power GaAs f.e.t.s, and deterioration of the microwave performance due to that capacitance is negligible.     

C.C.D.-addressed liquid-crystal displays

A charge-coupled device is described in which there is nondestructive charge sensing in every bit by using an integrated f.e.t. The f.e.t.s are capable of swinging up to 40 V across high-impedance loads, and it is shown that the device is suitable for receiving information in serial form and using it to address a liquid-crystal display.     

New structure of enhancement-mode GaAs microwave m.o.s.f.e.t.

This letter proposes a new feasible device structure of an enhancement-mode GaAs deep-depletion m.o.s.f.e.t. as an attractive alternative to the junction-gate f.e.t.s and describes its microwave properties. The device has been fabricated on a high-resistance epitaxial n?-layer by simple readily available technology without requiring the sophisticated control of the channel thickness needed for the conventional junction-gate f.e.t.s. The 'normally-off nature of the device can be explained on the basis of the substrate space-charge region extending over then?-layer. The microwave performance of the device can be favourably compared with that of currently achievable junction-gate normally-off f.e.t.s. Unilateral gain drops to zero at a frequency slightly above 7 GHz.     

V-shaped-gate GaAs m.e.s.f.e.t. for improved high-frequency performance

The idea of gate shaping in f.e.t.s was implemented into the GaAs-m.e.s.f.e.t. structure. A m.e.s.f.e.t. with 2 ?m gate length was fabricated, the measured m.a.g. data of which allow an extrapolation to an fmax of about 45 GHz.     

GaAs power f.e.t.s with semi-insulated gates

GaAs semi-insulated-gate f.e.t.s (s.i.g.f.e.t.s) have been fabricated by Ar+ bombardment in the gate region. The d c. characteristics and microwave performance are compared with those of conventional power m.e.s.f.e.t.s fabricated from the same slice. Up to 2.9W output power with 4dB gain has been obtained from s.i.g.f.e.t. devices at 8 GHz.     

J.F.E.T. bucket-brigade circuit: some recent experimental results

A bucket-brigade circuit implementation with junction field-effect transistors (j.f.e.t.) offers a significant improvement in maximum data rates for digital operation, and in maximum bandwidth for analogue operation. Some 10-stage monolithic j.f.e.t. brigades have recently been built and successfully operated at data rates of 50 MHz. In the Letter, the j.f.e.t. structure is briefly described and some experimental results are presented.     

Conversion gain of m.e.s.f.e.t. drain mixers

A theoretical analysis of the gain properties of m.e.s.f.e.t. drain mixers is presented. The m.e.s.f.e.t. model includes the nonlinearity of both the transconductance and the drain resistance. For a special case, a simple analytical expression for the gain is given. Numerical results for a typical example are briefly presented as an illustration.     

High peripheral power density GaAs f.e.t. oscillator

Peripheral power density (p.p.d.), i.e. the output power per Unit gate width is defined as a figure of merit for GaAs f.e.t. oscillators. An X-band oscillator circuit using series and shunt feedback is described and its performance characteristies indicated. It is shown that this GaAs f.e.t. oscillator circuit configuration has the highest peripheral power density.     

X and Ku band GaAs m.e.s.f.e.t.

A GaAs Schottky-barrier f.e.t. (m.e.s.f.e.t.) with a 1 ?m gate has been built, which is suitable for X band and Ku band applications. The unilateral power gain over the X band is above 9 dB and the noise figure is only 5 dB at 10 GHz.     

High-speed 1 ?m GaAs m.e.s.f.e.t.

By minimising parasitic series resistances, a GaAs m.e.s.f.e.t. with 1 ?m gate length was fabricated, possessing the highest known r.f. power gain, measured up to 18 GHz, for GaAs m.e.s.f.e.t.s.