Effect Of Oxide Thickness And Emitter Size On Ionization Damage Of PNP Transistor

Bipolar transistors have excellent characteristics and are widely used in space device electronic systems.Different structures and different gate oxide GLPNP transistors have different sensitivity to ionizing radiation damage.Therefore,it is of great significance to study the ionization damage effects of different gate oxide thickness GLPNP transistors and different structure GLPNP transistors.In this paper,GLPNP transistors with different gate oxide thickness and different structure are studied.Based on 1MeV electron irradiation test,combined with hydrogen immersion test,4200 semiconductor characterization system and deep level transient spectroscopy(DLTS)are used to test key Electrical performance parameters and radiation defects reveal the influence of gate oxide thickness and structure on the electrical degradation and defect evolution of GLPNP transistors..The results show that the current gain of GLPNP transistors with different gate oxide thickness decreases with the increase of irradiation fluence at 1 MeV electron irradiation.When the irradiation fluence is the same,the thinner gate oxide PNP transistor current gain degradation is more serious than the thicker gate oxide GLPNP transistor,which indicates that the thin gate oxide transistor is more sensitive to 1MeV electron irradiation damage.Irradiated by 1 MeV electron,the electrical properties of GLPNP transistors of different structures are significantly degraded with the increase of irradiati on fluence.When the irradiation fluence is the same,the device with the smallest emitter perimeter area ratio and the maximum base area has the largest radiation damage,and the structure with the largest perimeter area ratio and the minimum base area has the least radiation damage.After hydrogen immersion treatment,the electrical properties of all GLPNP bipolar transistors were significantly degraded with the increase of 1 MeV electron irradiation fluence.For a bipolar transistor with a thin gate oxide layer,the electrical properties degradation of the hydrogen immersed device is reduced compared to the case without hydrogen immersion at the same irradiation fluence.For a bipolar transistor with a thick gate oxide layer,the electrical properties of the device immersed in hydrogen are degraded at the same irradiation fluence compared to the case without hydrogen immersion.The electrical property degradation law of GLPNP bipolar transistors with different structures after hydrogen soaking treatment is similar to that of non-hydrogen soaking treatment.Through the separation calculation of the induced defects,it is known that the main factor affecting the degradation of the electrical properties of the transistors under different conditions is the increase of the interface-trap charge.Through the DLTS,compared with the thick gate oxide transistor,the peak value of the thin gate oxide transistor DLTS signal increases;after soaked the hydrogen,the thin gate oxide transistor signal peak shifts toward the high temperature direction,and the signal peak decreases,The peak value of the thick gate oxide transistor which soaked hydrogen is significantly increased.