Study On Enhancement Of Radiation Hardness Of In P-based Hemt With Double Si-doped Plane And Composite Channel

InP-based high electron mobility transistors?HEMTs?have lots of excellent characteristics such as high frequency,high gain,low power consumption,and low noise,which have attracted much attention in space electronic system such as satellite communication and deep space exploration.The space environment is rich in protons,and proton irradiation can cause the deterioration of electronic system or even failure,which tremendously reduce the reliability of the electronic system in space operation.Therefore,the enhancement of radiation hardness of InP-based HEMTs has become an urgent problem to prompt their space applications.Proton irradiation can induce vacancy defects in InP-based HEMTs,and decrease carrier concentration?n_s?and mobility???through carrier removal and scattering effects,which thus leads to the degradation of direct current?DC?and radio frequency?RF?characteristics.On this basis,this paper has proposed and optimized anti-irradiation structures of InP-based HEMTs,including structure with double Si-doped plane on both sides of channel layer,structure with double Si-doped plane above channel layer and structure with composite channel layers.The irradiation tolerance of improved structures have been compared with conventional single-doped and single-channel?Hereinafter referred to as conventional structure?.The main research results obtained in this paper are as follows:1.This thesis proposes the double Si-doped plane structure by inserting additional Si-doped plane under channel layer and above the original Si-doped plane,respectively.?1?Compared with the conventional structure:the native carrier concentration(n_s0)of the improved structure with double Si-doped plane on both sides of channel has been increased by approximately 11%.With the increase of percentage of the conventional structure is 0.15%-19.9%,while the value of improved structure has decreased to 0.04%-11.3%.The DC and RF characteristics for both structures gradually deteriorate with the increase of proton irradiation dose.The deterioration percentages of saturated channel current(I_DS,sat),the maximum transconductance(g_m,max),current gain cutoff frequency?f _T?and the maximum oscillation frequency(f_max)of conventional structure are approximately:4.5%-45.2%,2.9%-32.3%,1.65%-16%and 1.4%-10.1%.The value of the structure with double Si-doped plane on both sides of channel were approximately:2.97%-32.1%,2.1%-23.8%,1.19%-14.3%and 1.2%-8.3%.?2?Compared with the conventional structure,I_DS,sat,g_m,max,f _Tand f_maxof improved structure with double Si-doped plane above channel layer have increased approximately by 53.55%,12.29%,3.75%and 7.9%before proton irradiation.With the increase of irradiation dose,the decayed percentages of I_DS,sat,g_m,max,f _Tand f_maxof conventional structure are about:4.08%-40.36%,2.36%-25.59%,1.13%-15.79%and 1.63%-21.6%,which decrease to 2.27%-23.2%,1.61%-11.68%,0.67%-11.79%and 0.93%-16.21%for the improved structure with double Si-doped plane above channel layer.It can be known from the above that the radiation tolerance can be enhanced by inserting an additional Si-doped plane,which will increase n_s0and compensate for the carrier removal effect.Moreover,the higher the proton dose,the more obvious the superiority of irradiation reinforcement.2.In this thesis,an anti-irradiation structure based on In_0.53Ga_0.47As/In As/In_0.53(Al_0.7G_a0.3)_0.47As composite channel also has been proposed.Compared with the conventional structure,the?,I_DS,satand g_m,maxof the composite channel structure before irradiation have been increased by about 142.87%,65%and 110%,respectively.The electrical characteristics of the two structures deteriorate with the increase of the proton dose.The decline degree of I_DS,satand g_m,maxof conventional structure are about 25.2%-90.7%and 20.3%-74.4%,which improves to 10.4%-36.4%and 9.6%-45.3%for the structure with composite channel.It can be known that the structure with composite channel shows superior radiation tolerance.The higher?of composite channel can effectively compensate the scattering effect caused by irradiation induced defects.Meanwhile,the deep potential well by the In As layer could limit carriers within channel region.The research on the anti-irradiation structures with double Si-doped plane and composite channel could provide theoretical basis and technical support for radiation hardness of InP-based HEMTs and integrated circuits,and finally improve the stability and durability of relative electronic systems in space applications.