Determine the sheet resistance rsh ohmssquare the contact

Question

1. The optical transmittance T of a semiconductor wafer of thickness d is shown in Figure 1. Replicate this figure and draw the T- 1/λ curve where the semiconductor wafer is thinned, i.e. d is reduced. Justify your answer.

The reflectance remains the same:

T = (1-R)2e^-ad)/(1-R)²e^-2ad

2. Light is incident perpendicular on a Si wafer covered with a dielectric of thickness d and refractive index n. The reflectance versus wavenumber is shown Figure 2.

Determine the dielectric thickness.

Where n= 2

And the following may be useful:

d = λ₀λ₁/2Π(λ₁-λ₀)

3. Consider an n-type wafer containing small n⁺ regions. A four-point probe is placed on the wafer so that probe 1 of a conventional in-line four-point probe is placed on one of the n⁺ regions. The other three probes are on the n-portion of the wafer.

In this four-point probe, current enters probe 1 and leaves probe 4; the voltage is measured across probes 2 and 3. There are no n⁺ regions between probes 2 and 4. Is the correct sheet resistance measured in this case? Explain your answer

4. A transmission line measurement structure below gives R_T values as shown in the graph (Figure 3). The doping density ND in the n+ layer is uniform.

Determine the sheet resistance R_SH (ohms/square), the contact resistance R_C (ohms) and the doping density N_D (cm-3). Z (n+ layer width = 100µm, L= 25 µm, t = 2.5x10^-4 cm, µn = 50 cm²/Vs).

Answer 1

For the following electrical problem, by applying the basic concepts and theories of electrical solve the following numerical problems in a word document. Q1. Let suppose an n-type wafer having small n+ regions. A 4-point probe is put on the wafer in such a way that probe 1 of a conventional in-line four-point probe is put on one of the n+ regions. The other three probes are on n-part of the wafer. In this 4-point probe, present enters probe 1 and leaves probe 4; the voltage is evaluated across the probes 2 and 3. There are no n+ regions between probes 2 and 4. Is right sheet resistance evaluated in this case? Q2. The transmission line measurement structure below provides RT values as illustrated in the graph. The doping density ND in the n+ layer is uniform. Find out the sheet resistance RSH (ohms/square), the contact resistance RC (ohms) and the doping density ND (cm-3).