n- and p-channel m.o.s.f.e.t.s as Rayleigh-surface-wave detectors

We have studied the piezoresistance effect in an m.o.s.f.e.t. structure used as a Rayleigh-surface-wave transducer. The investigation was carried out over a large frequency range about a central value of 100 MHz. Results for silicon?m.o.s.f.e.t. n- and p- channel inversion layers are given.     

Boron segregation data for d.m.o.s. devices

A simple formula is given for the extent of boron depletion from the surface channel region of a d.m.o.s. f.e.t. during fabrication.     

Leak-compensated analog memory with pair m.o.s.f.e.t.s

A fast, simple, and relatively stable analog memory element is proposed, composed of two condensers and a pair of complementary m.o.s.f.e.t.s. The memory element was made sufficiently stable by the use of complementary m.o.s.f.e.t.s to enable a learning machine to complete the learning process within a comparatively short time.     

Silicon-on-insulator m.o.s.f.e.t.s fabricated on laser-annealed polysilicon on SiO2

N-channel-enhancement and light-depletion-mode m.o.s.f.e.t.s have been fabricated on laser-annealed 0.5 ?m polysilicon films, deposited on 1 ?m of SiO2 grown on single-crystal silicon substrates. Threshold voltages of 0.35?0.45 V and ?0.5 ? ?0.7 V and surface mobilities of 170 cm2/Vs and 215 cm2/Vs were obtained on the enhancement and depletion devices, respectively. These results compare favourably with values realised in silicon-on-sapphire (s.o.s.) and bulk N-m.o.s. devices. In addition, the measured source-drain leakage currents match the best reported values for s.o.s. devices.     

Test of the thermal-noise hypothesis in m.o.s.f.e.t.s

Evidence is given that, for m.o.s.f.e.t.s, another source o noise besides thermal noise must be operating in the conducting channel.     

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.     

Offset-voltage temperature-coefficient in dual m.o.s.f.e.t. source followers

A technique is given for predicting the approximate temperature coefficient of offset voltage of a differential m.o.s.f.e.t. source-follower arrangement incorporated in a unity-gain buffer amplifier set up for zero offset at room temperature. The prediction is dependent on only one measurement, using a bridge-circuit technique, and takes account of possible power-law differences in the nominally matched dual m.o.s.f.e.t.s.     

Subthreshold behaviour of e.s.f.i.-s.o.s. transistors

Theoretical and experimental results are presented which illustrate the influence of various parameters on the subthreshold behaviour of e.s.f.i.-s.o.s. transistors. The numerical analysis accounts for the thin silicon film and the existence of a second interface. A comparison is made with a corresponding bulk transistor, furthermore, between a two- and a one-dimensional analysis of e.s.f.i.-s.o.s. m.o.s.t. The agreement for real cases is found to be excellent.     

Noise behaviour of the m.o.s.f.e.t. at v.h.f. and u.h.f.

The optimum noise figures of an m.o.s.f.e.t. at u.h.f. and at pinch-off are calculated using a simplified equivalent circuit. The noise parameters are also determined experimentally. Theory and experiment are shown to be in good agreement. Noise parameters of the m.o.s.f.e.t. for the frequency range 0.1?0.8 GHz are given.     

Microwave capability of 1.5 ?m-gate GaAs m.o.s.f.e.t.

1.5 ?m-gate GaAs m.o.s.f.e.t.s have been fabricated by anodic oxidation, and the microwave capability has been examined. The maximum oscillation frequency fmax is 22 GHz and the noise figure is 6.1 dB at 8 GHz. The results are comparable to those of GaAs m.e.s.f.e.t.s.     

New n-channel m.o.s.f.e.t.s

By using plasma c.v.d. and lift-off, an n-channel m.o.s.f.e.t. with effective channel length of 0.4 ?m has been fabricated. Its main fabrication processes and obtained electrical characteristics are described.     

First anodic-oxide GaAs m.o.s.f.e.t.s based on easy technological processes

It is shown that a new technology results in the first native-oxide m.o.s.f.e.t.s. Their electrical behaviour is described.     

I.C.-compatible completely planar GaAs m.e.s.f.e.t.s. by selective diffusion

Completely planar GaAs m.e.s.f.e.t.s were produced by selective open tube diffusion from tin-doped spin-on SiO2 films. After the diffusion process no change in the surface morphology was observed in the doped regions. The evaluation of saturation currents of the m.e.s.f.e.t.s show very good homogeneity. Isolation between doped areas was excellent. Sample preparation and device results are presented; possible applications are outlined.     

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.     

n-channel inversion-mode InP m.i.s.f.e.t.

Capacitance/voltage and m.i.s.f.e.t. inversion-mode f.e.t. data are reported for p-type InP. It is shown that the surface of this material appears to be inverted at zero gate bias and that good inversion-mode (normally-off) device behaviour is possible.     

Micrometre-gate m.e.s.f.e.t.s on laser-annealed polysilicon

Schottky-barrier field-effect transistors (m.e.s.f.e.t.s) have been fabricated on uniformly doped laser-annealed polycrystalline silicon deposited on a silicon nitride insulator. The devices, which had aluminium Schottky-barrier gates and diffused n+ sources and drains but nonoptimised channel profiles, had about 65% the gm values of similar but optimised devices made on s.o.s. layers. Performance of these devices is considered adequate for certain innovative integrated-circuit technologies.     

Depletion-type m.o.s.f.e.t.s for low-temperature operation

Taking carrier freeze-out into account|a novel structure for depletion-type m.o.s.f.e.t.s suitable for low-temperature operation is proposed. Its channel consists of two regions; a relatively wide, low-impurity-density region and a relatively narrow, high-impurity-density region. It is estimated that the proposed structure has more square-law-like load character istics and higher current density than conventional ones.     

n-channel formation on semi-insulating InP surface by m.i.s.f.e.t.

InP m.i.s.f.e.t.s using Fe-doped semi-insulating material surface have been fabricated. The devices, composed of sulphur-diffused n-type source and drain and c.v.d. Al2O3 gate insulator, exhibited n-channel normally-off behaviour and a source drain capacitance two orders of magnitude smaller than that of p-InP m.i.s.f.e.t.s with the same dimensions.     

Implanted Si m.o.s.f.e.t.s for high-speed applications

Si m.o.s.f.e.t.s with a channel length of 0.8 ?m have been fabricated using boron implantation to adjust the threshold voltage. With microwave design appropriate to keeping the parasitics small, fmax values between 10 and 12 GHz are realised also with ion implantation. Large-signal switching times of 48 ps, small-signal switching times of 44 ps and delay times of 50 ps have been achieved.     

Four-quadrant multiplier using m.o.s.f.e.t. differential amplifiers

This letter describes an arrangement of two current-biased and one voltage-biased m.o.s.f.e.t. differential amplifiers. The circuit is suitable for a 4-quadrant multiplier of quite good linearity in a wide output-current range.