Boosting the total ionizing dose tolerance of digital switches by using OCTO SOI MOSFET

This paper performs an experimental comparative study of the total ionizing dose effects due to the x-ray radiation between the silicon-on-insulator (SOI) metal-oxide semiconductor field-effect transistors (MOSFETs) manufactured with octagonal gate geometry and the standard counterpart. Our main focus is on integrated transceivers for wireless communications and smart-power dc/dc converters for mobile electronics, where the transistor is used as the key switching element. It is shown that this innovative layout can reduce the total ionizing dose (TID) effects due to the special characteristics of the OCTO SOI MOSFET bird’s beak regions, where longitudinal electrical field lines in these regions are not parallel to the drain and source regions. Consequently, the parasitic MOSFETs associated with these regions are practically deactivated

OCTO Layout Variations as an Alternative to Mitigate TID Effects

This paper performs an experimental comparative study between the OCTO SOI MOSFET (octagonal gate geometry) and its derivations (different angles) as a total ionizing dose (TID) effects mitigation strategy. After a TID equal a 600 krad were analyzed the leakage current (ILEAK) behaviour in order to indicate the better configuration for digital applications in radioactive environment. The α angle equal to 53.1° achieved promising resultsfor low power and low voltage applications due ILEAK reduction in function of the TID

Boosting the Radiation Hardness and Higher Reestablishing Pre-Rad Conditions by Using OCTO Layout Style for MOSFETs

This manuscript has the objective to perform an experimental comparative analysis of the total ionizing dose influence in the Silicon-On-Insulator Metal-Oxide Semiconductor Field Effect Transistor implemented with the octagonal gate shape (OCTO) and the standard one (rectangular gate shape) counterpart, after a X-ray radiation exposure. The back-gate bias technique is applied in these devices to reestablish the threshold voltage and subthreshold slope that were degraded by the ionizing radiation effects. Since the octagonal layout style maintains a better electrical performance after radiation, a smaller back-gate bias to recover the pre-rad operation is required in comparison to the conventional counterpart. This is mainly because the parasitic transistors in the bird's beak region are practically deactivated by the particular octagonal gate geometry

Improving the X-ray radiation tolerance of the analog ICs by using OCTO layout style

This paper investigates and compares experimentally the total ionizing dose (TID) effects in the main analog parameters of the fully depleted (FD) OCTO Silicon-On-Insulator (SOI)n-type Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET) (OSM), that presents an octagonal gate geometry, versus its conventional (rectangular gate geometry) counterpart (CSM). The main analog parameters taken into account in this study are the drain current in saturation region (IDSsat), the maximum transconductance (gm-max), the transconductance (gm) over the drain current (IDS) ratio (gm/IDS), the unity voltage gain frequency (fT), intrinsic voltage gain (AV) and Early voltage (VEA). This work demonstrates that OCTO layout style achieved the same relative variation due the TID effects as the conventional for the main analog parameters, but keeping the higher electrical performance related to the LCE and PAMDLE effects. In addition the OSM had a higher tolerance in terms of gm-max, IDSsat and VEA relative variation and fT and AV performance in strong inversion regime

Comparative Experimental Study of X-Ray Radiation Effects in the Threshold Voltage between the OCTO and Conventional SOI nMOSFETs

This paper describes a comparative experimental study of the influence of Total Ionizing Dose (TID), due the X-ray radiation, in the threshold voltage (VTH) of the OCTO (OSM) and Conventional SOI nMOSFET (CSM). The threshold voltage becomes more negative at high X-ray doses in both devices. The impact of trapped charge in the buried oxide becomes more evident on the conventional device, while the octagonal device exhibits a lower change of the threshold values than the conventional, considering the same gate die area (Ag) and bias conditions

Total Ionizing Dose Effects on the Digital performance of Irradiated OCTO and Conventional Fully Depleted SOI MOSFET

This paper investigates and compares experimentally the total ionizing dose (TID) effects in digital parameters of the fully depleted (FD) OCTO Silicon-On-Insulator (SOI) n-type Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET) (OSM), that presents an octagonal gate geometry, versus its conventional (rectangular gate geometry) counterpart (CSM). The main digital parameters taken into account in this study are the threshold voltage (VTH), subthreshold slope (SS), on-state drain current (ION) characteristics. This work demonstrates that OCTO layout style achieved higher radiation tolerance in terms of VTH and SS relative variation and keeping the higher ION performance, due to the LCE and PAMDLE effects existent in the OCTO layout style. In addition the OSM had a significant improvement in terms of the leakage drain current (ILEAK), whereas the CSM ILEAK performance was degraded