Silicon Wafer Minority Carrier Life Time

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What Is Minority-Carrier-Lifetime?

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We would like to order 25x DSP, n-typ, FZ, 100mm, 1-0-0, 275 µm and 100x DSP, n-typ, FZ, 150mm, 1-0-0, 275 µm with the following minimum requirements: 4” Material 6” Material Resistivity (Ohm-cm): < 3 Minority carrier lifetime (ms): > 5.8 > 13 Thickness (µm): 280 ± 10 Total Thickness Variation (µm): < 3 < 1.5 Bow (µm): < 2 < 3.5 Could you provide those and if send a quotation for that? Also due to new German regulations if you want to participate in the tender I would need you to sign the self-certification in attachment 2. 

UniversityWafer, Inc. Replied:

The geometric specifications, specifically TTV, Bow and thickness tolerance, are extremely difficult. We can meet them, but the wafers would be very expensive. Also, I am surprised at the very tight specification on Bow without there being a corresponding specification on Warp. Please check if you can loosen some of your specifications.

We do have available 100mmØ FZ ingot and 150mmØ FZ ingot with resistivity <3 Ohmcm. However, I question if the Minority Charge Carrier Lifetime that you specified is achievable at the specified doping level (at Ro<3 Ohmcm).

The 100mmØ FZ ingot that we have available has resistivity (0.98-1.02)Ohmcm, but MCC Lifetime has not been measured on it.
Another such FZ ingot, from the same manufacturing process, with resistivity of 110 Ohmcm has measured MCC Lifetime of 11,558µs but with doping 30 to 100 times heavier, the MCC lifetime is bound to be much shorter.

The 150mmØ FZ ingot that we have available, with resistivity (1.01-1.02)Ohmcm, has measured MCC Lifetime of 1,571µs, but that is much shorter than you specified. Another such FZ ingot from the same manufacturing process, with resistivity of 16.8 Ohmcm has MCC Lifetime of 14,467µs but with heavier doping, the MCC lifetime is bound to be shorter.

If the ingots that we have available would be suitable for you then we would be happy to prepare a price quotation for the wafers that you specified.

Reference #252938 for wafer specs and pricing.

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Minority Carrier Lifetime Measurement

The performance indicator used to quantify the available efficiency of PV material is the Minority Carrier Life (MCL). The equation that describes the lifetime of the effective carrier is the diffusion coefficient. The effective minority life profile is given by taking into account both the surface recombination and the diffusion of the carrier, the simple thickness perpendicular to the surface plane being the entire surface of a carrier and its surface velocity being its diffusion velocity. [Sources: 0, 2]

The current minimum carrier lifetime measurement is performed from the surface of the carrier at a distance of 1 mm from its surface plane. As shown in line 152, which approaches curve 150, the current majority carrier life of a sample is determined by measuring the curve 154, as indicated in line 156, which is approximately equal to curve 156. The current minorities of the samples are determined from measurements on the slope of curve 155, suggesting that line 150 is approximately curve 152. [Sources: 1]

The lifetime of the minority carrier, obtained from traditional PRT measurements, is in the range of 4 - 20 ns. There is a difference between the lifetimes of minorities and majority members, which is discussed further below. [Sources: 0, 1]

The current life of the minority carrier can be linear or non-linear over time intervals. It can vary in the range of 0.5 - 10 ns, with a maximum of 4 - 20 ns and a minimum of 2 ns. [Sources: 1]

The u-trmrr approach therefore has the advantage that the photon emission is effectively stretched over long periods of time, which can increase the lifetime of the minority carriers in the range of 0.5 - 10 ns. In summary, we present a new approach to measuring the majority lifetime of a nonlinear semiconductor material. It is still the subject of our invention today to provide a method for measuring the life span of minority carriers in terms of their linearity and sensitivity. It remains the state of the art to measure it in a semiconductor material that possesses both linearity and sensitivity. [Sources: 1, 4]

This method measures the life span of minority carriers in the range of 0.5 - 10 ns in a nonlinear semiconductor material with regard to its linearity. [Sources: 0]

In addition, time-resolved microwave reflection (TMR) is used to extract the lifetime of minority carriers in the 0.5 - 10 ns range. N drift layer, carbon implantation and annealing increases the lifetime of the minority carrier from 7ms to 24ms. [Sources: 3, 6]

In this work, we used data from low excess densities to determine the life span of minority carriers as a function of temperature. U - TRMRR results match the lifetime obtained from conventional TMR and TRPL measurements, indicating improved performance in measuring the lifetime of low emitting substrates with long service life. [Sources: 3, 4, 6]

From this we can conclude that the life span of minority carriers is extended with the temperature depending on the number of minority carriers per mm2. As you can see, the life of the majority carriers increases significantly with increasing temperature, and this means that their life span should increase at any temperature. Note that in order to reach full temperature - a dependent parameterization of the life span in indium - it would be necessary to determine the ratio between the maximum and minimum temperature, and the minimum and maximum density for each of these two parameters. [Sources: 0, 5]

For example, see Boda et al., # 214, published in 2014, in her work "Measuring the minority carrier life of semiconductor materials," which reveals the lifetime of the majority and minority carriers of indium in a single-layer semiconductor. [Sources: 1]

The life of the minority carriers achieved by these two methods is distributed over different CD compositions, but it is clear that the measurement results of all three methods show an increasing trend in the value of the life of the minority carriers over time. If we apply such experiments and methods, the majority carriers - lifetime values obtained from these methods - will show that the values of the minority life - life of carriers increase with the increase in CD composition. [Sources: 0]

The average life of minority carrier systems can be calculated from the forward-to-reverse current ratio as shown in Figure 5. The relation between forward and reverse currents is represented by the ratios of forward and reverse currents. [Sources: 0]

The photovoltaic decay constant can determine the best fit for the experiment. Therefore, the lifetime of the minority carrier can be correlated with the constant decay times and is defined as the ratio of the forward to reverse current ratio to the reverse currents. The RC discharge cannot be excluded from the photOVolta decay process, as the illuminated bias light almost does not influence the transient photvolt curve. Consequently, a life of a minority is achieved that is greater than the real value, since the rc discharge process delays the degradation and hardening of the photovolarity. [Sources: 0, 1]












Minority Carrier Life Time of Silicon Wafers

After becoming a free electron in the conduction band, an electron gives up its energy and falls into a h ole in the covelent bond of the valence band. This is known as recombination.

This process is known as recombination. The time period from when an electron moves from the conduction band until recombination isa call the lifetime of the electron-hole pair. Thermal energy leads to the continual creation of electron-hole pairs followed by their recombination.

Below are just some silicon wafers that we sell with higher carrier lifetimes. Other specs and diameters in small and large quantities also available.

Item Dia Type/Dopant Orien Thick Pol Res ohm-cm Lifetime
E239 150mm N/Ph (100) 825um As-Cut FZ 7,025-7,856 7,562μs
5325 150mm N/PH (100) 725um DSP FZ 57-62 15,700μs
6846 100mm P/B (100) 250um DSP FZ 1-3 1,700μs
6510 76.2mm P/B (100) 350um DSP FZ 1-5 1,500μs



Michael Quirk, Julian Serda, Semiconductor Manufacturing Technology