P-stop designs for reducing electric field strength at implant edges

In designing the radiation-tolerant silicon microstrip sensors, the onset of microdischarge must e expelled above the maximum operation voltage. The difficulty is enhanced in the n-in-p sensors, with the existence of p-n junction in the n-strips and the existence of p-stop structures. The device simulation program enabled to understand the electric fields in detail and to optimize the design to be robust against the microdischarge. The potential of the p-stop is the fundamental. In the common p-stop structures, the narrowest p-stop width has the shallowest potential and generating the least electric field strength (Emax). The potential of the split p-stops near to the n-implant in the combined p-stop does not have a potential closer to that of the n-implant. The symmetric location of p-stop has the least Emax. The Emax increases as the strip pitch decreases less than 80 microns but stays the same as the pitch widens larger than 80 microns. The onset voltage of Punch-thru protection (PTP) is governed by the gap between the n-implants, N-N gap, even with the existence of p-stop in between.