3. (a) Calculate the bandwidth of the silicon photodiode in Figure Q3. Include a diagram of the equivalent circuit that
Posted: Tue May 24, 2022 8:57 am
configuration was used. explain why adding an intrinsic silicon
layer can improve the bandwidth and calculate the layer thickness
needed to obtain a bandwidth of 2.5GHz if only Trc is
considered
(C for your choice of Wd in Q3(b). calculate the actual
bandwidth if both Tr and Try are considered. comment on the
relative contributions of the time constants for this device
(D) the phtotodiode in Q3(a) is illuminated by a light source
and absorbs 1.5mW of optical energy at 650nm. calculated the
photocurrent Ip and the total noise on this current. the bandwidth
of the system has been limited to 25MHz for this measurement.
Assume standard room temperature 25 degree Celsius
(E) give two applications where photodiodes could be used,
discussing what device parameters are important for these
applications
3. (a) Calculate the bandwidth of the silicon photodiode in Figure Q3. Include a diagram of the equivalent circuit that allows you to determine TRC. Comment on the relative contribution between the two time constants TR and TRC. Figure Q3 Photodiode schematic and specifications. AR Coating SIO2 Anode SIN P Active Area Depletion Region P/N| Junction Bulk N Type N+ Back Contact Diffusion Back Metalisation Cathode Depletion Region Width (wa) 1 μm Photodiode Shape Square Photodiode length 0.55 mm Silicon relative permittivity 11.68 Saturation Velocity (Vs) 3x105 8.85x10-12 Permittivity of free space Load Impedance Responsivity @650nm 50Ω 0.65 AW-¹ [9]