Question

Question 2 Soalan 27 ממ CLOAD VDD I osat Equation 1 [Persamaan 1] Equation (1) describes the dependency of propagation delay with important device parameters. Based on that equation, discuss how circuit performance is enhanced in Integrated Circuits fabrication technology. The answer should include both front-end and back-end process integration aspects and other associated equations. (Persamaan 1 menunjukkan kebergantungan kelewatan penyebaran bersama parameter-parameter yang lain. Berdasarkan persamaan tersebut, bincangkan bagaimana prestasi litar dapat ditingkatkan dalam teknologi fabrikasi litar bersepadu. Jawapan tersebut mestilah memasukkan kedua-dua aspek bersepadu proses fron-end' dan 'back-end' dan juga persamaan-persamaan yang berkaitan.) (25 Marks/ 25 Markah)

Answer 1

(1)These relationships imply that for a given manufacturing process, improvements in individual gate delays are possible by reducing the load impedance $C_{LOAD}$ or by increasing the current gain of the transistors. Reducing the load impedance is possible by controlling physical aspects of the design (the specific gate layout). Alternatively,increasing $\beta$ of the devices (recall that   $\beta\alpha \frac{W}{L}$)

is typically accomplished by controlling the value of a process known as transistor or gate sizing. (Typically, the device channel length is chosen to be the minimum permitted by the technology and therefore cannot be decreased to further increase $\beta$ .)

Transistor sizing, however, has limit its area requirements may limit the maximum channel width W, and increasing W will also increase the capacitance of the gates.

Photonic integrated circuits (PICs) the light-based equivalent of electronic ICs carry signals via visible and infrared light. Optical materials with adjustable refractive index are essential for reconfigurable PICs as they allow for more accurate manipulation of light passing through the materials, leading to better PIC performance.

Current programmable PIC concepts suffer from issues such as volatility and/or high optical signal losses – both of which negatively affect a material’s ability to keep its programmed state