An investigation of ionizing radiation damage in different SiGe processes

Different SiGe processes and device designs are the critical influences of ionizing radiation damage. Based on the different ionizing radiation damage in SiGe HBTs fabricated by Huajie and an IBM SiGe process, quantitatively numerical simulation of ionizing radiation damage was carried out to explicate the distribution of radiation-induced charges buildup in KT9041 and IBM SiGe HBTs. The sensitive areas of the EB-spacer and isolation oxide of KT9041 are much larger than those of the IBM SiGe HBT, and the distribution of charge buildup in KT9041 is several orders of magnitude greater than that of the IBM SiGe HBT. The result suggests that the simulations are consistent with the experiment, and indicates that the geometry of the EB-spacer, the area of the Si/SiO2 interface and the isolation structure could be contributing to the different ionizing radiation damage.

Proton induced radiation effect of SiC MOSFET under different bias

Radiation effects of silicon carbide metal–oxide–semiconductor field-effect transistors(SiC MOSFETs)induced by 20 MeV proton under drain bias(V_(D)=800 V,V_(G)=0 V),gate bias(V_(D)=0 V,V_(G)=10 V),turn-on bias(V_(D)=0.5 V,V_(G)=4 V)and static bias(V_(D)=0 V,V_(G)=0 V)are investigated.The drain current of SiC MOSFET under turn-on bias increases linearly with the increase of proton fluence during the proton irradiation.When the cumulative proton fluence reaches 2×10^(11)p·cm^(-2),the threshold voltage of SiC MOSFETs with four bias conditions shifts to the left,and the degradation of electrical characteristics of SiC MOSFETs with gate bias is the most serious.In the deep level transient spectrum test,it is found that the defect energy level of SiC MOSFET is mainly the ON2(E_(c)-1.1 eV)defect center,and the defect concentration and defect capture cross section of SiC MOSFET with proton radiation under gate bias increase most.By comparing the degradation of SiC MOSFET under proton cumulative irradiation,equivalent 1 MeV neutron irradiation and gamma irradiation,and combining with the defect change of SiC MOSFET under gamma irradiation and the non-ionizing energy loss induced by equivalent 1 MeV neutron in SiC MOSFET,the degradation of SiC MOSFET induced by proton is mainly caused by ionizing radiation damage.The results of TCAD analysis show that the ionizing radiation damage of SiC MOSFET is affected by the intensity and direction of the electric field in the oxide layer and epitaxial layer.

Estimation of enhanced low dose rate sensitivity mechanisms using temperature switching irradiation on gate-controlled lateral PNP transistor

The mechanisms occurring when the switched temperature technique is applied,as an accelerated enhanced low dose rate sensitivity(ELDRS)test technique,are investigated in terms of a specially designed gate-controlled lateral PNP transistor(GLPNP)that used to extract the interface traps(Nit)and oxide trapped charges(Not).Electrical characteristics in GLPNP transistors induced by ^(60)Co gamma irradiation are measured in situ as a function of total dose,showing that generation of Nit in the oxide is the primary cause of base current variations for the GLPNP.Based on the analysis of the variations of Nit and Not,with switching the temperature,the properties of accelerated protons release and suppressed protons loss play critical roles in determining the increased Nit formation leading to the base current degradation with dose accumulation.Simultaneously the hydrogen cracking mechanisms responsible for additional protons release are related to the neutralization of Not extending enhanced Nit buildup.In this study the switched temperature irradiation has been employed to conservatively estimate the ELDRS of GLPNP,which provides us with a new insight into the test technique for ELDRS.