For Electronics Engineers only?

Question

* What do you think will happen to the storage delay if the diode cross sectional area was decreased? Explain your reasons.
* Based on your answer to the previous question, explain why technical advances in semiconductor size reduction leads to advances in communication speeds.
[neat and organized answer is required]

Answer 1

My intuition on this makes me believe that the storage delay should decrease as the cross sectional area is decreased. In general, as the size decreases, usually the capacitance also decreases. A lower capacitance value will store less charge and the charge that is stored can be discharged faster with a given conductance/resistance in the circuit. This translates to allowing faster switching speeds and higher bandwidths. The limiting value is usually the time constant set up by these unintended capacitors and the resistance of the bulk material or external circuitry. Anything that lowers this will result in smaller time constants which will provide higher speed operation of the device or the system using the device.

However, the storage delay of diodes is a little different and has to do with removal of charge carriers from the pn junction when the diode becomes reverse biased. A larger cross sectional area means there are more of these charge carriers to remove which could result in a longer storage delay. Similar to plates of a capacitor, where capacitance is proportional to the area of the plates.

Answer 2

Storage delay is unchanged. It's a physical property of the diode based on doping density and recombination current, unaffected by physical area of the junction.

Storage delay has minimal effect on the processing speed of modern transistor circuits. It's all about capacitance and voltage.

Re-read yuor textbook.

Answer 3

Please study hard yourself. Don't ask people to do homework for you. You ain't going anywhere with people doing stuff for you.