Articles you may be interested inEffects of postdeposition argon implantation on the memory properties of plasmadeposited silicon nitride films J. Appl. Phys. 66, 3131 (1989); 10.1063/1.344148 Annealing effect on the resistivity of polycrystalline silicon films passivated with plasmadeposited siliconnitride films Structural and electrical properties of plasma-deposited silicon nitride (SiN) have been investigated. The compositional ratio of Si to N estimated by Auger analysis is found to be uniform in the direction of the film thickness. The numbers ofSi-H and N-H bonds of the order of _10 21 lcm 3 have been obtained by calculating the vibrational spectra. The two types of trapping states which are responsible for the Poole-Frenkel conduction are found in SiN from the current DL TS measurement. The barrier height at the SiNISi interface determined by the internal photoemission ranges from 1.7 to 2.5 eV, being dependent on the film thickness. From these results, current transport mechanisms through SiN films are quantitatively discussed, and it is demonstrated that the carrier transport is dominated by the Fowler-Nordheim tunneling at low temperatures and by the Poole-Frenkel conduction at high temperatures.

A SiNx film deposited by electron cyclotron resonance plasma CVD has been successfully applied as a surface passivant for Hg0.7Cd0.3normalTe n+p diodes. The ECR‐plasma CVD assures low temperature deposition of SiNx film on normalHgCdTe . The SiNx has an excellent interface with normalHgCdTe with a surface‐state density as low as 1×1011 cm−2eV−1 and a low fixed charge of −1.4×1011 cm−2 . Measurement of flatband shifts after exposure to humidity verify that the SiNx is more moisture resistant than the conventional normalZnS passivant. A diode false(λnormalco=5.4 μnormalmfalse) passivated with SiNx had a zero bias resistance of 4×1010 normalΩ false(normaldiode area=4.8×10−5 cm2false) at 77 K.

We developed a 256 x 256 element HgCdTe hybrid infrared focal plane array (IRFPA) for the 8 to 10 j.tm band. We used three technologies to develop this high-performance, long-wavelength, large-scale IRFPA. The first innovation was to glue a sapphire substrate to a thinned Si readout circuit to reduce the thermal expansion mismatch with a HgCdTe diode array fabricated on a CdZnTe substrate. The second was to fabricate an interlaced switched-FET readout circuit using a 3 im CMOS process. This readout circuit has a storage capacity of more than iO electrons and two video outputs capable of a 3.5MHz data rate. The third was a HgCdTe diode array with an anodic sulfide passivation film and an optimized cutoff wavelength to reduce dark current and achieve high sensitivity. The noise equivalent temperature difference (NETD) was 0.06 K using f/2.5 optics. After 1000 thermal cycles (300 K-80 K), there were no significant indium bump failures nor notable degradation in detector performance.

We investigated the formation of cluster defects in HgCdTe materials by numerical simulation. The equations used for the simulation include change in the activation energy for Hg vacancy diffusion dependent on the local cadmium composition. This study demonstrated how defects grow during thermal treatment. We simulated the annealing process for initial composition fluctuations in uniform n-type Hg0.TsCd022Te. When the local composition fluctuations increase, we found that the concentration of vacancies around the initial core increases because of the composition difference between the initial core and bulk region. Concurrently, if the fluctuation range is narrow, the resulting large constant for interstitial diffusion accelerates this process. We determined that the critical fluctuation range is in the order of 50 nm for annealing at 150~ The concentration of clustering vacancies around the initial core reached 1016 cm -a, meaning that the conductivity of the cluster region changed to the p-type. We conclude that such cluster defects have a structure consisting of a core surrounded by a p-type shell.

We have investigated the reverse current -voltage characteristics of both 3 -5 tm and 8 -I0 im band HgCdTe photodiodes under background illumination in the temperature range of 40 K to 120 K. The experimental results show that the differential resistance of reverse biased photodiodes decreases with an increase in the incident photon flux density. In the higher reverse biased illuminated photodiodes, breakdown occurs. The reverse differential resistance is limited by this breakdown mechanism. In order to determine the causal mechanism, we calculated the photocurrent multiplication resulting from the electron impact ionization in the photodiode depletion region. For the calculation, we applied Shockley's " Lucky electron " equation assuming that only electrons multiply the photocurrent. The calculated reverse differential resistance -voltage characteristics agrees well with the measured results. The calculated differential resistance at a low reverse bias voltage as a function of incident photon flux density corresponds to the measured results in the temperature range of 40 K to 100 K. This indicates that the photocurrent multiplication by electron impact ionization occurs in the photodiode depletion region. In the low temperature region, the measured differential resistance increases with the decrease in temperature. This is caused by the acceptor freeze -out effects. We concluded that the differential resistance -voltage characteristics of HgCdTe photodiodes are limited by the effect of photocurrent multiplication, and the photomultiplication effect is limited by the carrier freeze -out in the low temperature region.