Simulation studies of the n+n− Si sensors having p-spray/p-stop implant for the SiD experiment

Silicon Detector (SiD) is one of the proposed detectors for the future International Linear Collider (ILC). In the innermost vertex of the ILC, Si micro-strip sensors will be exposed to the neutron background of around 1–1.6×1010 1 MeV equivalent neutrons cm−2 year−1. The p+n−n+ double-sided Si strip sensors are supposed to be used as position sensitive sensors for SiD. The shortening due to electron accumulation on the n+n− side of these sensors leads to uniform spreading of signal over all the n+ strips and thus ensuring good isolation between the n+ strips becomes one of the major issues in these sensors. One of the possible solutions is the use of floating p-type implants introduced between the n+ strips (p-stops) and another alternative is the use of uniform layer of p-type implant on the entire n-side (p-spray). However, pre-breakdown micro-discharge is reported because of the high electric field at the edge of the p-stop/p-spray. An optimization of the implant dose profile of the p-stop and p-spray is required to achieve good electrical isolation while ensuring satisfactory breakdown performance of the Si sensors. Preliminary results of the simulation study performed on the n+n− Si sensors having p-stop and p-spray using device simulation program, ATLAS, are presented.