Research On Ionizing Radiation Effect Of 600V SOI RESURF LDMOS

At present,the research on the ionizing radiation effect of semiconductor devices at home and abroad mainly focuses on the low-voltage MOSFET(Metal-Oxide Semiconductor Field Effect Transistor)structure and the SOI(Silicon On Insulator)material preparation process,there are few reports on the radiation effects and hardening methods of power semiconductor devices.This article first introduces SOI LDMOS(Lateral Double-diffused MOSFET)devices and the radiation environment faced by semiconductor devices,and then introduces the RESURF(REduced SURface Field)technology and field plate technology,two commonly used techniques in LDMOS design.Finally,the ionizing radiation effect of semiconductor devices and its hardening technology are introduced.This article takes two RESURF structure LDMOS(Single RESURF LDMOS and Double RESURF LDMOS)as the starting point to study the TID effect(Total-Ionizing-Dose Effect)on LDMOS,and compare the two structures to resist radiation The pros and cons of performance.Finally,a 600V thick SOI LDMOS device was developed,and the TID effect was studied on the device.Two device structures,Single RESURF LDMOS and Double RESURF LDMOS,were simulated and optimized on the SOI material of 40?m epitaxial silicon layer and 3?m buried oxide layer,and the influence of the TID effect on the two structures wascompared through simulation.A positive charge of 1E12 cm-2 is set at the interface between the buried oxide layer and the silicon,and the gate oxide layer is also charged in proportion to the thickness.The BV(Breakdown Voltage)of Single RESURF devices degrades from 586.8V to 581.8V,with a rate of change of 8.52‰;the BV of Double RESURF devices degrades from 769.1V to 770.8V,with a rate of change of-2.21‰.In terms of output characteristics,the Idlin(linear current)of the Single RESURF device increased from 3.54E-08A to 3.99E-08A,the Idsat(saturation current)increased from 1.83E-05A to 2.89E-05A,and the Idlin and Idsat increased by 12.7%and 57.9%respectively.The Idlin of the Double RESURF device increased from 9.18E-08A to 9.76E-08A,the Idsat increased from 3.99E-05A to 5.51E-05A,and the Idlin and Idsat increased by 6.32%and 38.1%respectively.A 600V thick SOI LDMOS device with a double-layer floating field plate was developed,and the TID effect was studied on the device.In the simulation,a positive charge of 1E12 cm-2 is set at the interface between the field oxide layer and the silicon.At the same time,the gate oxide layer and the buried oxide layer also add charges in proportion to the thickness(the effect is equivalent to a total dose of 300 krad(Si)irradiation),and the BV of the device degrades from 707.6V to 333.9V,with a rate of change of 52.8%.The Vth(threshold voltage)degrades from 2.6V to 2.3V,and the rate of change is 11.5%.The Idlin increased from 5.49E-08A to 6.88E-08A,an increase of 20.3%.The Idsat increased from 2.40E-05A to 7.09E-05A,an increase of 195%.Finally,tape-out and radiation experiments were carried out.Under fresh conditions,the BV of the device is 656V,the Vth is 3V,and the Idsat can reach 2.238mA.After the total dose of 100 rad(Si)is irradiated in the on state,the Idsat of the circular device degrades from 1.79mA to 2.14mA,which is 19.6%higher than that in the fresh state.The Vth degrades from 2.51V to 1.77V,which is 0.74V lower than in the fresh state.After the total dose of 100 krad(Si)is irradiated in the off state,the Idsat of the circular device degrades from 1.83mA to 2.25mA,which is an increase of 22.9%compared to the fresh state.The Vth degrades from 3.02V to 2.12V,which is 0.9V lower than in the fresh state.Due to device problems,the breakdown voltage cannot be measured,only the Ioff(leakage current)when Vd=400V is measured.In the on state,after 150 krad(Si)irradiation,the device's Ioff=5.285E-09A.In the off state,after receiving 150 krad(Si)irradiation,the device's Ioff=1.282E-09A.