Browsing by Author "J.L.Chu"

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Large-Signal Analysis of BARITT Diodes
(交大學刊編輯委員會, 1973-02)
褚冀良
;
施敏
;
J.L.Chu
;
S.M.Sze
Large-signal properties of p+νnp and associated BARITT (Barrier Injection Transit Time)diodes are analyzed. An accurate computer program(Sempak) is used which considers the space-charge balance, dependence of carrier mobilities on impurity concentration and electric field, and carrier generation and recombination. The static properties of BARITT diodes are also considered. General expressions for the flat-band voltage and the differential reactance are obtained. The results show that the p+νnp structure is the best choice which gives optimum performances both in static and microwave characteristics.
Thermionic Injection and Space-Charge-Limited Current in Reach-Through p+np+ Structures
(交大學刊編輯委員會, 1972-01)
褚冀良
;
施敏
;
J.L.Chu
;
S.M.Sze
The current transport mechanisms of reach-through p+np+ and its related structures have been studied.It has been established that when the applied voltages is slightly greater than the reach-through voltage, at which the n layer is completely depleted, the current increases exponentially with voltage by thermionic injection mechanism. The current-voltage relationship is given by J= A*T^2 exp〔-q(VFB -V)^2/4kTVFB〕where A* is the effective Richardson constant, T the temperature, V the applied voltage, and VFB the flat- band voltage defined as qNDL^2/2εS where ND and L are the ionized impurity density and the length of the n layer respectively. When the injected carrier density rises to a value comparable to the impurity density the space- charge-limited (SCL) effect causes the current to vary less rapidly with the applied voltage . The SCL effect is derived based on an accurate expression of the velocity-field relation, i.e., vs/(1+Es/E),where vs is the scattering-limited velocity and Es is the critical field given by the ratio of vs to the low-field mobility. In the hogh current limit we obtain the linear current-voltage expression J≈qNDvs(V/VFB). Experimental structures are made from epitaxial n on p+ silicon substrate with an epitaxial layer thickness of 8.5 μm and doping concentration of 5*10^14cm^-3. The second p+ layer of about 1μm is formed by diffusion. Good agreement have been obtained between the experimental results and theoretical predictions.
高辛雷射光束之幾何特性
(交大學刊編輯委員會, 1976-04)
褚冀良
;
J.L.Chu
This paper is a review of the Gaussian Laser beam propagation properties from the point of view of the Geometrical optics. It is meant to be tutorial in nature and useful in scope. And emphasis is placed on formulations, derivations and examples which lead to basic understanding and on results which bear practical significance.