The properties of a metal-oxide-metal (M-O-M) tunneling detector are presented and the parameters influencing its operation are discussed. The theory of operation and experimental results for small as well as large signals are presented. The polarity reversal at large-signal levels is predicted theoretically and observed experimentally.
We have studied the transport mechanisms in thin film (≈ 2000 Å ) hydrogenated α-Si structures used as programmable antifuses in Field-Programmable-Gate-Arrays (FPGA) The antifuse was simulated using a back-to-back Schottky model for a metal/Si/metal thin film incorporating the thermionic-emission diffusion model for the metal-semiconductor contacts. The model predicts the current transport in the low voltage and high voltage regions. In the intermediate voltage range a linear field dependence of the barrier lowering is observed in the experimental results which leads to higher currents than predicted with the image force barrier lowering in the simulations. An important observation is that carrier multiplication is essential for breakdown which is evidence of impact ionization in α-Si. The permanent breakdown condition is modelled thermally, based on the steady- state solution to the heat equation.
We have fabricated a YBa2Cu30,(YBCO) array of five Josephson junctions designed with additional inductive coupling lines(A1CLs). The junctions in this array were dcbiased in parallel to oscillate coherently in-phase and integrated with AICLs to improve the impedance matching between this array and external circuits such as a waveguide. The effect of AICLs was investigated by studying its influence on the currentvoltage characteristics of the Josephson junction array(JJA) under external microwave irradiations with frequency of 22 GHz. The experimental results show that the behavior of the Shapiro-steps depends upon the effective inductance of AICLs which affects the total impedance and microwave coupling. We were able to obtain an oscillation frequency of about 73 % of the maximum available frequency calculated from the characteristic voltage of the Josephson junctions in the array at a temperature of 12 K. By calculating the total impedance of the array, we obtained the suitable parameters of the array for microwave coupling with waveguide for various values of inductance, ac frequencies and number of Josephson junctions.
A phenomenological formulation which incorporates both avalanche and tunneling mechanisms in an IMPATT diode is given. Here tunneling is viewed as a field-dependent carrier source. An electron after being field emitted may gain sufficient energy from the field to cause ionization. In this formulation, pure avalanche and pure tunneling appear as the two extreme cases of the general problem. The resultant general dc I- V characteristic shows the dominance of tunneling at low voltages and the onset of the multiplication at higher voltages as observed experimentally. A small-signal admittance of an IMPATT oscillator with tunneling has been calculated. Under some conditions tunneling may increase the negative conductance. However as tunneling dominates, the negative conductance deteriorates and the oscillator will operate in the tunnel transit-time mode. Tunneling invariably shifts the frequency for optimum negative conductance upwards. The threshold frequency for negative conductance varies as the square root of current density for large multiplication factors as expected. However, for small ones it converges to a value determined only by the drift transit time. The general admittance expression reduces to that of pure avalanche and pure tunneling under the prescription ωa → ω as M → ∞ and ωa → ωaz as M → 1, respectively. ωa, ωa0, and ωaz are the modified avalanche frequencies for the general case, pure avalanche, and pure tunneling, respectively.
Siang-Ping KwokHughes R e s e a r c h C e n t e r , T o r r a n c e , C a l i f o r n i a T h i s p a p e r d e s c r i b e s t h e d e s i g n , f a br i c a t i o n a n d c h a r a c t e r i s t i c s o f a new dev i c e c a p a b l e o f s w i t c h i n g l a r g e m i c r owave power a t extremely low d r i v e power l e v e l s . The new d e v i c e i s a novel res i s t o r -i n s u l a t o r -s e m i c o n d u c t o r ( R I S ) s t r u c t u r e w h i c h s w i t c h e s a microwave s i gnal between two t e r m i n a l s by t h e a p p l i c at i o n o f a D.C. b i a s o n a t h i r d , o r c o n t r o l , t e r m i n a l . The d e v i c e e m b o d i e s s e v e r a l u n i q u e f e a t u r e s i n c l u d i n g t h e u s e o f res i s t i v e t i t a n i u m d i o x i d e as a g a t e elect r o d e a n d t h e u s e o f a n i n s u l a t i n g T i O 2 / S i 0 2 c o m p o s i t e d i e l e c t r i c a s t h e g a t e i n s u l a t o r . The d e v i c e h a s e x h i b i t e d ' a d i o d e OFF/ON r a t i o i n e x c e s s o f 1 5 0 0 , a n i n s e r t i o n loss of 1 . 2 dB and has switched 1 0 0 watts of Rf power a t a c o n t r o l l e v e l of less t h a n luwatt i n a 3 . 5 G H z 4 -b i t p h a s e s h i f t e r .
Articles you may be interested inLow damage fully self-aligned replacement gate process for fabricating deep sub-100 nm gate length GaAs metal-oxide-semiconductor field-effect transistors J. Vac. Sci. Technol. B 28, C6L1 (2010); 10.1116/1.3501355 TiW nitride thermally stable Schottky contacts to GaAs: Characterization and application to selfaligned gate field effect transistor fabrication Characterization of reactively sputtered WN x film as a gate metal for selfalignment GaAs metal-semiconductor field effect transistors J. Vac. Sci. Technol. B 4, 1392 (1986); 10.1116/1.583463 Orientation effect reduction through capless annealing of selfaligned planar GaAs Schottky barrier fieldeffect transistors Appl. Phys. Lett. 43, 865 (1983); 10.1063/1.94531 Orientation effect of selfaligned source/drain planar GaAs Schottky barrier fieldeffect transistors
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