In this paper we present a novel, quadruple well process developed in a
modern 0.18mu CMOS technology called INMAPS. On top of the standard process, we
have added a deep P implant that can be used to form a deep P-well and provide
screening of N-wells from the P-doped epitaxial layer. This prevents the
collection of radiation-induced charge by unrelated N-wells, typically ones
where PMOS transistors are integrated. The design of a sensor specifically
tailored to a particle physics experiment is presented, where each 50mu pixel
has over 150 PMOS and NMOS transistors. The sensor has been fabricated in the
INMAPS process and first experimental evidence of the effectiveness of this
process on charge collection is presented, showing a significant improvement in
efficiency.Comment: 15 pages, 10 figures, submitted to "Sensors