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.     

Current-kink noise of n-channel enhancement e.s.f.i.-m.o.s. s.o.s. transistors

An experimental study of the low-frequency-noise properties of n-channel epitaxial silicon films on insulator m.o.s. s.o.s. transistors has been performed. The measurements show an excessive noise contribution at drain voltages corresponding to the current-kink effect for temperatures ranging from 4.2 to 300 K.     

Switching in m.i.s.m. and m.i.s.i.m. structures

Switching has been observed in metal?thin-insulator?n-p+ structures, where the thin insulator is SiO2, or polycrystalline silicon. In this letter two alternative structures are discussed in which the n-p+ junction is replaced by a Schottky barrier. In the second device proposed two thin-insulator structures back-to-back are shown to exhibit bidirectional switching.     

GaAs m.a.o.s.f.e.t. memory transistor

A new non-volatile memory device is reported. This device is a GaAs m.o.s.f.e.t. with charge storage in the gate in which is a double oxide structure of aluminium oxide and GaAs native oxide, both oxides are grown anodically. The fabrication of the device is described and the results of initial measurements on the charging and charge retention properties are presented.     

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.     

Wide-range monolithic bipolar?j.f.e.t. c.c.o.

A new monolithic current-controlled oscillator (c.c.o.) has been realised in a j.f.e.t.-bipolar technology. Its main advantages are a highly-linear seven decade frequency range and easy temperature compensation for frequency and output voltage.     

V.H.F. and u.h.f. Gunn-effect oscillators

In this letter, the use of the Gunn device as a broadband negative resistance, somewhat analogous to a tunnel diode, is explored. v.h.f. and u.h.f. oscillators are described; the frequency is determined by an external resonant circuit and is very nearly independent of the parameters of the Gunn-effect sample.     

More active RC filters using the d.v.c.c.s./d.v.c.v.s.

Novel configurations using a differential-voltage-controlled current source, differential-voltage-controlled voltage source (d.v.c.c.s./d.v.c.v.s.) as the active building block are described. The configurations assume that the active building block is divided into two independent parts initially.     

New V-groove double-diffused m.o.s. (v.d.m.o.s.)

A new V-groove double-diffused m.o.s. (v.d.m.o s.) is proposed which combines the V-groove technology and the double-diffused m.o.s. (d.m.o.s.) technology. The fabrication processes arc qualitatively described. The gate is located on the vertical V-shaped surface, and the effective channel length is controlled by the vertical-diffusion process of the double-diffusion step. The v.d.m.o.s. is expected to have a faster speed and higher production yield than the ordinary d.m.o.s.     

V.P.E. GaAs m.e.s.f.e.t. structure using oxygen injection during buffer layer growth

GaAs m.e.s.f.e.t. structures with high-resistivity buffer layers were prepared by introducing oxygen into the deposition system during growth. The electrical properties of the buffer layers are independent of the oxygen content of the gas phase over a large range of partial pressures. The characteristics of devices prepared with such layers are excellent.     

Photo-f.e.t. method: high-resolution deep-level measurement technique using a m.e.s.f.e.t. structure

M.E.S.F.E.T.s with channels produced by diffusion from spun-on emulsion films into semi-insulating GaAs were investigated by a new technique: the photo-f.e.t. method. The advantage over the commonly used photocapacitance method is outlined and measurements are presented.     

Power m.o.s.f.e.t. linear h.f. amplifiers

N-channel silicon m.o.s. transistors for h.f. power applications have been fabricated which are optimised for linear amplification. These devices exhibit 2 W output power and 11 dB power gain at 630 MHz in class-A operation. The intercept point for third-order intermodulation distortion is 48dBm, which is considerably more than the same data obtainable with bipolar transistors.     

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.     

Herrn O. Univ.-Prof. Dipl.-Ing. Dr. Richard Eier zur Emeritierung

Ohne Zusammenfassung     

Performance of GaAs power m.e.s.f.e.t.s

Power performance results at 4 GHz are summarised for GaAs m.e.s.f.e.t.s ranging in size from 4 to 16 mm gate periphery. A double-chip 16 mm unit operated at 24 V source-drain bias produced 13.5 W with 3 dB gain and 10.7 W with 8.1 dB gain. Although lack of perfect power and gain scaling is observed, the degradation in output power of the 16 mm devices was only 1 dB compared to the smaller devices.     

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.     

Normally-off m.e.s.f.e.t. with fast switching behaviour

Normally-off m.c.s.f.e.t.s, fabricated on an insulating GaAs substrate with a vapour-phase-grown double layer (n?/n), showed a d.c. characteristic with a good saturation range and a switching response of 35 ps risetime.     

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.     

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.     

Integrated n.m.o.s. operational amplifier for c.c.d. transversal filters

An integrated operational amplifier employing a new high-gain input stage and implemented with n.m.o.s. enhancement devices is reported. The circuit has been designed with reference to the output differential-charge amplifier of a c.c.d. transversal filter. The performance parameters of the amplifier are presented.