Boosting the MOSFETs matching by using diamond layout style

Using the Hexagonal Layout Style for MOSFETs to Boost the Device Matching in Ionizing Radiation Environments

“…In this scenario, the Diamond (hexagonal gate geometry) layout style for MOSFETs is an example of this approach, according to Fig. 1, which illustrates an example of a layout of an n-channel Diamond SOI MOSFET (DnM) [8][9].…”

“…The first effect is called the Longitudinal Corner Effect (LCE). It is responsible for boosting the Resultant Longitudinal Electric Field (RLEF) and subsequently the drain current, transconductance, etc., compared to the Conventional (rectangular gate shape) MOSFETs (CM), n-type (CnM) counterparts, considering the same gate areas (AG), Ws and bias conditions [8][9]. The second effect is called the Parallel Association of MOSFETs with Different Channel Length Effect (PAMDLE).…”

“…As the DnM structure can be considered as the parallel connections of infinitesimal small conventional (rectangular) MOSFETs with different channel lengths (Ls) [indicated by the PAMDLE], each drain current (IDS) tends to further flow by those infinitesimal MOSFETs that present the smallest channel lengths (Ls), which are found, initially, near the device edges. Therefore, the PAMDLE is responsible to decrease its effective channel length (Leff) [Equation 1] compared to the one of the CnM counterpart, in case that they have the same AG and W, and consequently the drain current of DnM tends to be higher than the one of the CnM counterpart [8][9]. The third effect is called Deactivation of Parasitic MOSFETs in Bird´s Beak Regions Effect (DEPAMBBRE), because the RLEF lines in the Bird's Beaks Regions (BBRs) of the DnMs are curved, instead of straight and parallel lines, as happens for the CnM counterparts [8][9].…”

“…Therefore, the PAMDLE is responsible to decrease its effective channel length (Leff) [Equation 1] compared to the one of the CnM counterpart, in case that they have the same AG and W, and consequently the drain current of DnM tends to be higher than the one of the CnM counterpart [8][9]. The third effect is called Deactivation of Parasitic MOSFETs in Bird´s Beak Regions Effect (DEPAMBBRE), because the RLEF lines in the Bird's Beaks Regions (BBRs) of the DnMs are curved, instead of straight and parallel lines, as happens for the CnM counterparts [8][9]. Consequently, the parasitic MOSFETs in the BBR of DnM are always electrically deactivated [8][9].…”

“…The third effect is called Deactivation of Parasitic MOSFETs in Bird´s Beak Regions Effect (DEPAMBBRE), because the RLEF lines in the Bird's Beaks Regions (BBRs) of the DnMs are curved, instead of straight and parallel lines, as happens for the CnM counterparts [8][9]. Consequently, the parasitic MOSFETs in the BBR of DnM are always electrically deactivated [8][9]. Thus, those three effects occur simultaneously in the DnM structure and they are responsible for boosting the DnMs electrical performance (LCE and PAMDLE) and Total Ionizing Dose (TID) tolerance (DEMPABBRE) in comparison to those found in the CnM counterparts [8][9].…”