V.V. Milenin

Ohmic contacts for microwave diodes

Au-TiN-n/sup +/-Si and Au-Ti-Pd/sub 2/Si-n/sup +/-Si ohmic contacts were fabricated using thermal and magnetron evaporation onto n/sup +/-silicon substrates with various concentrations of free electrons. Diode test structures with such contacts were fabricated using photolithography. The effect of thermal annealing and /sup 60/Co /spl gamma/-irradiation on the I-V curves and stability of both contacts and test structures was investigated. The data obtained were compared to the results of mathematical simulation of both tight contacts and those with a SiO/sub 2/ interlayer. The calculations and experiments demonstrated that such tight low-resistance contacts with Schottky barrier based on palladium silicides are tolerant to short-term thermal annealing up to 600/spl deg/C and to /spl gamma/-irradiation in the 10/sup 2/ to 3/spl times/10/sup 5/ Gy total dose range.

Effect of surface roughness on the properties of ohmic contacts to GaAs

Au/Ge/TiB/sub x//Au ohmic contacts to n-GaAs with textured surface have been developed and investigated. Two types of microrelief morphology (quasi-grating and dendrite-like), that are perspective for Solar Cell and sensor application, have been obtained by wet chemical anisotropic etching. The surface morphology and structural perfection were studied by AFM technique and x-ray diffractometry measurements. The effect of surface roughness on the value of contact resistivity and its lateral distribution has been investigated. The qualitative model for nonuniformity of ohmic contact formation caused by the dependence of intrinsic stresses on the interface roughness has been drawn to explain experimentally observed spread of electrical parameters.

RADIATION PROCESSING OF CR-GAAS CONTACTS

We report on the influence of 60Co gamma‐radiation upon the properties of Cr‐GaAs diode structures. Auger depth profiling proved that while a low dose of radiation made the transition region wider, higher doses caused its narrowing. Radiation treatment affected the Schottky barrier height and ideality factor favourably.

On a diffusion mechanism of intrinsic stress relaxation in AuGeGaAs contacts

Abstract A striped ordered structure in the interface plane was observed by means of TEM in the AuGeGaAs heterosystem. This effect seems to result from a diffusion mechanism of elastic stress relaxation, and not from the ordinary dislocation mechanism.

Diffusion effects at PtGaAs interfaces

Abstract The effect of γ irradiation and electric field on the properties of PtGaAs contacts is studied. It is found that such treatments cause reversible diffusion of platinum at the interface. This accounts for the relaxation of mechanical stresses in the contact.

Highly sensitive microwave detecting Au-TiB/sub x/(ZrB/sub x/)-n-SiC 6H diodes

We present electrical parameters and characteristics of microwave detecting Au-TiB/sub x/(ZrB/sub x/)-n-SiC 6H diodes. The possibility of using these diodes as power sensors for application in a wide power range (including power up to 1 W) was studied. It is shown that heat-resistant Schottky-barrier diodes (fabricated using magnetron sputtering onto SiC wafers) based on TiB/sub x/(ZrB/sub x/) interstitial phases demonstrate voltage sensitivity of 1800

Experimental studies of microwave oscillator modules based on Si IMPATT diodes

3500 mV/mW at input power of 10/sup -7/ W.

Nonuniformities in metal-semiconductor contacts

We report our experimental results concerning the oscillator modules intended for the millimeter wavelength range (operating frequency of 30-39.5 GHz). They were fabricated. using silicon double-drift IMPATT diodes whose ohmic contacts involved antidiffusion layers based on TiN/sub x/ interstitial phases. The output power of these modules is 10-50 mW.

Effect of /spl gamma/-irradiation on the electrophysical parameters of metal/GaAs barrier structures with textured interfaces

For some metal-semiconductor contacts we investigated the effect of nonuniformity size and distribution on the excess current for forward branches of I-V curves at low voltages. The curves were taken before and after rapid thermal annealing. It is shown that distributions of nonuniformity heights at metal surfaces and metal-semiconductor interfaces are described by Gaussians whose parameters are given.

Some features of interaction between phases in Ge/GaAs heterostructure

We investigated (i) morphology of the GaAs surface with a quasigrating-type microrelief and (ii) current flow mechanism in the Au/GaAs barrier structures formed on the above textured surface. Both Atomic Force Microscopy (AFM) and measurements of electrical (I-V and C-V) characteristics were used. We have found both semiconductor and interface parameters, as well as studied how they depend on /sup 60/Co /spl gamma/-irradiation in the 10/sup 3//spl divide/10/sup 7/ Gy dose range. The parameters measured were shown to be tolerant to such irradiation doses.