The annealing test was performed at room temperature, following an annealing time of approximately 700 hours.įigure 3 V BE vs. The delay between irradiation and remote testing was approximately 45 minutes. On-wafer DC measurements of the samples were made at room temperature (T = 300K) using a Keysight Technologies 4142 semiconductor analyzer before irradiation, after irradiation and after annealing. For reference, 1 rad(Si) = 0.94 rad(GaAs). The SHBTs were irradiated without bias in a gamma cell using a Co 60 source, with a dose rate of about 50 rad(Si)/sec and irradiation times of 5.5, 16.5, 38.5 and 55 hours, equivalent to a gamma total dose of 1, 3, 7 and 10 Mrad(Si), respectively, for the test samples. The base-emitter is an InGaP/GaAs heterojunction and the emitter area of the transistor is 1.0 x 20 μm 2, IC is 8 mA maximum. The InGaP/GaAs SHBTs used in this study are commercial products from WIN Semiconductors (see Figure 1). The increase in V CE(sat) is related to gamma irradiation-induced defects in the base-collector space charge region (SCR). This article reports experimental data showing the V CE(sat) of InGaP/GaAs single heterojunction bipolar transistors (SHBTs) increases significantly after exposure to gamma irradiation and subsequent annealing. In logic applications, the increase can decrease noise margin significantly due to an increase in the on-state voltage drop of the output. 6 In analog circuits, an increase in V CE(sat) can affect the gain of an amplifier, depending on its quiescent point, and can cause output distortion. An important and undesirable problem is degradation of the collector-emitter saturation voltage, V CE(sat), after irradiation because it affects the operation of analog and digital circuits. 1-5 The recent growth of wireless and other high-end communication applications continues to draw attention to the long-term reliability of its performance under irradiation. The GaAs HBT is widely used in the design of high speed integrated circuits because of its superior performance. Analysis shows the increase of saturation voltage is mainly caused by irradiation-induced defects in the base-collector space charge region, including its bulk and periphery. It is found that the saturation voltage increases by more than 0.1 V after exposure to gamma irradiation with a total dose of 10 Mrad(Si) and subsequent annealing at room temperature. We report the investigation of gamma irradiation effects on the collector-emitter saturation voltage of InGaP/GaAs heterojunction bipolar transistors (HBTs).
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