Calculate the dimension of the channel width
Course:- Electrical Engineering
Reference No.:- EM131469642

Assignment Help
Assignment Help >> Electrical Engineering

The design work involves producing layouts for circuit in Fig. 1. Such layouts correspond to the patterns developed on the masks, for use in the fabrication process, as discussed in lectures. Each of the layouts MUST be drawn on a graph paper with stipulated scale (e.g. 1µm per cm). The four masks that need to be defined are: device area, gate stripe, contacts and metal pattern. Produce individual layouts for each device i.e. A, B, C and RL, and also the overall layout for the circuit, in terms of the minimum feature size. Make sure to include the alignment errors between the layouts and minimise the area used.

Description: The circuit in Fig. 1 consists of a two-stage inverter, where the output from the 1st inverter Vo' is fed into the input gate of the 2nd inverter. The driver of both inverters consists of enhancement type n- MOS transistors A and B. Note these transistors have identical aspect ratios. It can be assumed that the threshold voltage VT to be 0.3 V. For the loads, the 1st inverter has an (active) saturated n-MOS transistor C, whilst the 2nd inverter has an (passive) implanted resistor load RL.


Note the resistance value of C is equal to the resistance RL, and similarly, the resistance of A is identical to the resistance of B, when the transistors are on.

For your design, calculate the dimension of the channel width W for the drivers and respective dimensions of W and L for C and RL. To assist you with the calculation, you can select appropriate value for the output voltage Vo', which corresponds to the logic 0 condition, assuming a logic 1 input to be equal to VDD = 5 V. Note the value of Vo' needs to be lower than VT of the driver B in order to ensure that the transistor remains off at logic 0. The value depends on the ratio of the resistances between the driver and load for each inverter. Also for the implanted resistor RL, you can assume a sheet resistance of 150Ω/square, where each square is defined by minimum feature size. Note for the layouts you must take account the alignment accuracy λa, which can also be assumed to be equal to the minimum feature size. For your calculation, you can assume the following values for the parameters:

i. Minimum feature size λm = 0.5 µm
ii. Supply voltage VDD = 5V (Logic 1 input)
iii. Threshold voltage VT = 0.3 V
iv. Sheet resistance 150 Ω/square
v. Device constant is given as,

β = (μCo)W/L = (βo)W/L

where βo = 1.8 x 10-4 AV-2

For the Report: Give a brief description of the circuit operation in Figure 1. Include all your calculations and reasons for the assumptions made. Represent all respective individual and overall design layouts in scaled graph paper, in terms of minimum feature size. Use different shading to indicate the different regions and include the alignment errors between respective layouts.


Verified Expert

In the given question, a design was to be analysed mathematically and the values of resistances to be determined which has been done. Also, a layout was to be drawn on graph paper whose image I have attached.

Put your comment
View Conversion
  1. user image

    Following are the details and attachment provided by the student. Please be sure if your tutor can do the assignment or not. you should initially focus on the 1st inverter stage, and subsequently calculate the value for the ratio of (W/L)A to (W/L)C. You should then ‘select’ appropriate values for respective aspect ratio of the two devices, however making sure the calculated ratio of the two is maintained. When selecting the values, you need to take into account that appropriate alignment error is included within respective layouts, and also minimal area is utilised. You will thus find that the selection process for the respective aspect ratios can be reiterated. Make sure to include all your findings in the report. For the 2nd stage inverter, the driver A is the same as B, so the same aspect ratio applies. The load devices, C and RL have the same resistance however have different dimensions since one is a passive load and the other an active load. So you should work out appropriate value for L and W of RL.

Ask Question & Get Answers from Experts
Browse some more (Electrical Engineering) Materials
You have available a temperature-to-voltage transducer which generates a voltage of 5 V at 160°C and an alarm which activates at -15 V and is off for larger voltages. Sketch
Hence, the preceding condition ensures that a pulse at any instant will not interfere with the amplitude of any other pulse at its center. Find p(t). Is p(t) unique in the s
A 1.5 kW heater and a 5 hp induction motor are operated from a 208V, three-phase supply. The motor has a full load efficiency of 80% and a full load power factor of 0.85. Wh
1- Find F(s) for = A[ a cos(ßt) + b sin(ßt)] u(t) and plot and the poles and zeros in the S- plane. 2- find f(s) for = 2d(t) +4e^-2t cos(2t) u(t) and plot and the poles and ze
The armeture leakage reactance is 0.10 per unit on the generator rating as abase. Find(a) the unsaturated value of the synchronous reactance inohms per phase and per unit, (
A 4-bit shift register is shifted six times to the fight. If the initial content of the register is 1101, find the content of the register after each shift if the serial inp
A measurement of the rate at which a capacitor will store a charge on its plates is called The opposition to the flow of current which results in the continual interchange o
For a moving average filter with bk coefficients equal to 0.2 and given that the input to the filter starts at sample x[n], how many input samples are required to define all