X-ray Radiation Hardness of Fully-Depleted SOI MOSFETs and Its Improvement

TL;DR

This study investigates the effects of X-ray radiation on fully-depleted SOI MOSFETs, identifying charge-related causes of current changes and proposing methods to enhance radiation hardness.

Contribution

It provides a detailed analysis of radiation-induced charge effects in FD-SOI MOSFETs and suggests improvements like higher PLDD dose and thinner BOX for better radiation hardness.

Findings

n-MOSFET drain current increases by 15% after irradiation

p-MOSFET drain current decreases by 20% after irradiation

Higher PLDD dose and thinner BOX improve radiation hardness

Abstract

X-ray radiation hardness of FD-SOI n- and p-MOSFET has been investigated. After 1.4 kGy(Si) irradiation, 15% drain current increase for n-MOSFET and 20% drain current decrease for p-MOSFET are observed. From analysis of gmmax-Vsub, the major cause of n-MOSFET drain current change is the generated positive charge in BOX. On the other hand, the major cause of p-MOSFET drain current change is the radiation induced gate channel modulation by the generated positive charge in sidewall spacer. It is confirmed that the p-MOSFET drain current change is improved by higher PLDD dose. Thinner BOX is also proposed for further radiation hardness improvement.