Open‐circuit voltage decay: moving to a flexible method of characterisation

Open-circuit voltage decay (OCVD) is a method to characterise minority carrier effective lifetime (). It is non-destructive, simple and low-cost. It has been mainly used in silicon p-n junctions. is not only a very important parameter to optimise device design but also to supervise process steps. It is not the only parameter we can obtain by OCVD. Due to the intrinsic space charge region capacitance of a p-n junction, the doping level of the lowest-doped region () and built-in potential () are extractable. Moreover, it is also possible to obtain the shunt resistance () value when it has a significant effect on the p-n junction behaviour. The authors first applied the well-established one-diode model in a transient regime to simulate OCVD signal. In a second step, they used an optimisation algorithm to fit the experimental curve of a silicon diode to extract , , and . These values were compared to those obtained from C–V and I–V. Results are promising and demonstrate for the first time, the flexibility of the OCVD method. It opens up the perspective for the development of add-on features of the method and for measuring short lifetime.