R.N. Mitra

Bio: R.N. Mitra is an academic researcher from University of Calcutta. The author has contributed to research in topics: Frequency drift & Static induction transistor. The author has an hindex of 2, co-authored 4 publications receiving 10 citations.

Photoselective Deposition of Copper and Nickel on Non-Conducting Substrates by Alkaline Electroless Baths at Room Temperature

Abstract: Interest in the metallization of dielectric substrates such as ceramics, plastics is growing because of their wider applications in electronic industries, namely in the fabrication of MIC's, HIC's etc. In this paper an attempt has been made to deposit copper and nickle using room temperature electroless baths on pre-selected areas of alumina and FRP substrates using PdCl2 as activator. The process offers a uniform dense deposit of Ni/Cu selectively on the substrates. For full coverage of the metal on the substrate it has been found that either AgNO3 or PdCl2 as activator has the same effect. The process yields a dense deposit of Cu and Ni having good adherence to the substrates.

Analysis of a Bismuth Sulfide/Silicon Junction for Building Thin Film Solar Cells

Abstract: Feasibility of combining p-type crystalline Si (c-Si) of 200―8000 nm in thickness with an n-type bismuth sulfide (Bi 2 S 3 ) thin film of 300 nm in thickness for thin film solar cell is analyzed. Theoretical analysis shows that the high optical absorption coefficient (10 5 cm ―1 ) of Bi 2 S 3 results in a light-generated current density (J L ) of >20 mA/cM 2 for a c-Si(200 nm)Bi z S 3 (300 nm) stack at a combined film thickness of 500 nm, and with an open circuit voltage (V oc ) of nearly 600 mV. Proof-of-concept cell structures were prepared on p-type c-Si wafers of electrical resistivity 1 Ω cm. Any oxide layer at the interface significantly deteriorates the cell parameters. In a cell prepared using evaporated n-Bi 2 S 3 on (p) c-Si, J sc is 3 mA/cm 2 ; V oc is 360 mV; and η is 0.5%; which improved to: 7.2 mA/cm 2 , 485 mV and 1.7%, respectively, after heating the cell in forming gas. A cell with an Sb 2 S 3 (40 nm) thin film as an antireflective coating on Bi 2 S 3 , produced: J sc of 10 mA/cm 2 ; V oc of 480 mV; and η of 2.4%. Theoretical simulation suggests that better cell fabrication could lead to: J sc of 26 mA/cm 2 ; V oc of 600 mV; and η of 10%.

Assessing model adequacy and selecting model complexity in integrated-circuit simulation

Abstract: A method is described that selects, for each transistor in a circuit, the model of least complexity that will give acceptable accuracy. The capability to assess model adequacy derives from a self-consistency test in which the values of currents and voltages computed in a simulation of the circuit behavior are compared with onset parameters, to determine whether these computed values are consistent with the approximations underlying the device models used in the simulation. The onset parameters for a model are the terminal currents and voltages above or below which the model fails to give a satisfactory representation of device behavior. The authors set forth the onset parameters for the Ebers-Moll model and discuss their determination by terminal measurement and by calculation based on the transistor makeup. The paper limits consideration to the static behavior of transistors operating in the forward-active mode.

Derivation of the emitter-collector transit time of heterojunction bipolar transistors

Abstract: Various expressions for the emitter-collector transit time of a heterojunction bipolar transistor (HBT) can be found in the literature. It is not obvious whether the product of the emitter contact resistance and the base-emitter capacitance should be included in the emitter-collector transit time expression. This paper theoretically demonstrates that the above product does not appear in the transit time expression. Additional physical insights observed from the derived transit time expression and comparison to a similar expression for homojunction bipolar transistors will be discussed.

On the variation of cut-off frequency with emitter end concentration of a diffused base transistor

Abstract: The effect of mobility degradation at high impurity concentrations on the cut-off frequency of a diffused base transistor with exponential impurity profile in the base has been considered analytically. It has been shown that the cut-off frequency exhibits a maximum with increase in emitter and concentration. The results are compared with those of complementary error function and Gaussian base impurity profiles.