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The pre- and post-irradiation effects on the DC electrical characteristics of 100 MeV Phosphorous (P7+) and 80 MeV Nitrogen (N6+) ion-irradiated NPN transistors were studied in the dose range from 600 krad (Si) to 100 Mrad (Si). The different electrical characteristics, such as Gummel characteristics, excess base current (ΔIB = IB-Post – IB-Pre), current gain (hFE), damage constant (K) and output characteristics, were measured in situ after ion irradiation. The considerable increase in the base current (IB) at lower VBE and slight decrease in the collector current (IC) at higher VBE were observed after ion irradiation. The C–V measurements revealed that the doping concentration (Nd) was found decreased, while the built-in potential (Vbi) increased after irradiation. The ion-irradiated results are compared with 60Co gamma-irradiated results in the same dose range. The SRIM simulation was performed to understand the range of ions and energy loss in the transistor structure. The SRIM simulation showed that 100 MeV P7+ and 80 MeV N6+ ions can easily pass through the active region of transistors by creating ionization and displacement damages in the device structure. The irradiation results showed that ions induce more degradation in the electrical characteristics when compared to 60Co gamma radiation at the same dose range. [ABSTRACT FROM AUTHOR]

Total ionizing dose effects induced by 1 MeV electron and 5 MeV proton on the dc electrical characteristics of 200 GHz silicon germanium heterojunction bipolar transistors (SiGe HBTs) were investigated. These results were compared with60Co gamma irradiation results to understand the linear energy transfer effects on the electrical characteristics of SiGe HBTs. The different electrical parameters like forward and inverse mode Gummel characteristics, excess base current (${\boldsymbol \Delta } I_{\mathbf {B}}$), current gain ($\boldsymbol {h}_{\mathbf {FE}}$), and output characteristics ($\boldsymbol {I}_{\mathbf {C}}$ - $\boldsymbol {V}_{\mathbf {CE}}$) were systematically studied before and after irradiation. The electrical characteristics of irradiated SiGe HBTs degrade with an increase in total dose. The more degradation in device parameters was observed in case of 5 MeV proton irradiated HBTs when compared to other radiations. The irradiated devices were also subjected to isochronal annealing to analyze the recovery of electrical parameters. [ABSTRACT FROM AUTHOR]

The total dose effects of 1 MeV electrons on the dc electrical characteristics of silicon NPN transistors are investigated in the dose range from 100 krad to 100 Mrad. The different electrical characteristics such as Gummel characteristics, excess base current (ΔIB), dc current gain (hFE), transconductance (gm), displacement damage factor (K) and output characteristics were studiedin situas a function of total dose. A considerable increase in base current (IB) and a decrease inhFE,gmandICSatwas observed after 1 MeV electron irradiation. The collector–base (C–B) junction capacitance of transistors was measured to estimate the change in the effective carrier concentration. After 1 MeV electron irradiation, a considerable degradation in capacitance was observed. The plot of (1/C2) versus voltage shows that the effective carrier concentration and built-in voltage (Vbi) increase marginally upon 1 MeV electron irradiation. The results of 1 MeV electron irradiation were compared with 1 MeV proton and Co-60 gamma irradiation results in the same dose range. The degradation for 1 MeV electron and Co-60 gamma-irradiated transistors was significantly less when compared to 1 MeV proton-irradiated transistor. The 1 MeV proton, 1 MeV electron and Co-60 gamma-irradiated transistors were subjected to isochronal annealing to analyze the recovery of the electrical parameters. [ABSTRACT FROM AUTHOR]

The Silicon NPN rf power transistors were irradiated with 180 MeV Au 14+ and 150 MeV Ag 12+ ions in the dose range of 1 Mrad to 100 Mrad. The SRIM simulation was used to understand the energy loss and range of these ions in the transistor structure. The different electrical parameters such as Gummel characteristics, excess base current (∆ I B ), dc current gain ( h FE ), transconductance ( g m ), displacement damage factor ( K ) and output characteristics were studied systematically before and after irradiation. These results were compared with lower linear energy transfer (LET) ions such as 50 MeV Li 3+ , 95 MeV O 7+ , 100 MeV F 8+ , 140 MeV Si 10+ and 175 MeV Ni 13+ ions in the same dose range. The degradation for 180 MeV Au 14+ and 150 MeV Ag 12+ ion irradiated transistors was significantly more when compared to lower LET ions, indicating that the transistors are vulnerable to higher LET ion irradiations. Isochronal annealing study was conducted on the irradiated transistors to analyze the recovery in different electrical parameters. After isochronal annealing, the recovery in h FE and other electrical parameters was around 67% for Ag 12+ ion irradiated transistors and 60% for Au 14+ ion irradiated transistors. [ABSTRACT FROM AUTHOR]

The total dose effects of 50 MeV lithium (Li3+) ions on 200 GHz (8HP) silicon-germanium heterojunction bipolar transistors (SiGe HBTs) are studied in total doses ranging from 300 krad to 10 Mrad. The different electrical characteristics, such as the Gummel characteristics, dc current gain (hFE), neutral base recombination, avalanche multiplication of carriers (M-1) and output characteristics (IC-VCE), were studied before and after Li3+ ion irradiation. The results of 50 MeV Li3+ ion irradiation on SiGe HBTs are compared with 60Co gamma irradiation results in the same dose ranges. [ABSTRACT FROM AUTHOR]

Abstract: The dc characteristics exhibited by NPN power transistors are studied systematically before and after irradiation by 100MeV F8+ ions and 50MeV Li3+ ions in the dose range of 100krad to 100Mrad. The transistor parameters such as excess base current (ΔI B=I Bpost–I Bpre), dc current gain (h FE), transconductance (g m), and collector-saturation current (I Csat) were studied before and after irradiation. The damage factors (k) for h FE were calculated for ion irradiated transistors using Messenger–Spratt relation. The base current (I B) was found to increase significantly after ion irradiation and this in turn decreases the h FE of the transistors. The g m decreases significantly after ion irradiation. Moreover, the output characteristics of irradiated devices also show that the collector current (I C) in the saturation region (I Csat) decrease with increase in ion dose. The observed change in these characteristics may be due to the ion induced generation–recombination (G–R) centers in emitter-base (E-B) spacer oxide and the ion induced point defects and their complexes in the transistor structure. [ABSTRACT FROM AUTHOR]

N-channel depletion MOSFETs were irradiated with 4 MeV Proton and Co-60 gamma radiation in the dose range of 100 krad(Si) to 100 Mrad(Si). The electrical characteristics of MOSFET such as threshold voltage ( V th ), density of interface trapped charges (Δ N it ), density of oxide trapped charges (Δ N ot ), transconductance ( g m ), mobility ( μ ), leakage current ( I L ) and drain saturation current ( I D Sat ) were studied as a function of dose. A considerable increase in Δ N it and Δ N ot and decrease in V th, g m , μ , and I D Sat was observed after irradiation. The results of 4 MeV Proton irradiation were compared with that of Co-60 gamma radiation and it is found that the degradation is more for the devices irradiated with 4 MeV Protons when compared with the Co-60 gamma radiation. This indicates that Protons induce more trapped charges in the field oxide region when compared to the gamma radiation. [ABSTRACT FROM AUTHOR]