Cross-coupling latch resistors are a prime method of mitigating single event upsets. Scaling has dramatically reduced ability of using this technique because of the restricted space available for these parts and high temperature coefficient (TCR) of polysilicon based resistors. This paper presents results of a study of electrical properties of Al 1-x In x N film resistor which offers distinct advantage over polysilicon resistors. The film was grown on silicon nitride by magnetron sputter deposition at room temperature. Sheet resistance of 8-10kΩ/ was reproduced. The resistor is quite stable from minus 55˚C to +125˚C with TCR of -0.09%/˚C and lower.To the best of our knowledge, this is the first time that this form of material engineering has been studied for mitigating single event upsets. We established two dominant sets of growth conditions. Results are tabulated in table I below for film before annealing. Samples 1, 4 and 5, were grown under similar plasma composition of 80% argon and 20% nitrogen. For these samples, aluminum composition was set at 80%, 40% and 20%. We found that a shift from 80% to 40% in aluminum caused a reduction of film resistance from 3.6MΩ/ to 32kΩ/ . Further reduction of aluminum composition from 40% to 20% caused a factor of three reduction is resistance to 12.3kΩ/ . We then varied nitrogen composition while keeping the metal composition constant. Samples 2 and 4 had metal composition at Al60/In40. Sample 2 had nitrogen gas at 30% while sample 4 was set at 20%. We observed that a change of nitrogen composition from 20% to 30% resulted in more than one order of magnitude reduction of sheet resistance from 32.4kΩ/ to 2.8kΩ/ . Samples 5 and 6 had metal composition of Al20/In80. For this set of samples, the growth was at 20% for sample 5 and 30% for sample 6 in nitrogen. A factor of six reduction of sheet resistance from 12.7kΩ/ to 2.2kΩ/ resulted. We attributed this reduction of resistance to nitrogen vacancies occurring as shallow donors (see figure 1a). Aluminum in aluminum nitride is known to have deep-level excitations with a range of thresholds from 0.8eV to 4.2eV. As shown in figure 1a below, aluminum vacancy (V Al ) creates a triplet state in the lower part of the band gap which is occupied by three electrons and can be filled with three more electrons, i.e., V Al is a triple acceptor [1]. Under n-type conditions, the triply charged aluminum vacancy V 3-has the lowest formation energy. It has been established that in Al x Ga 1-x As [2],[5], from a given fraction x of aluminum content and up, silicon lowers its energy by a large lattice relaxation and the consequent capture of a second electron in the so called DX transformation represented by equation (1) below. Experimental results suggest similar process in Al 1-x In x N.(1) Here d is a substitutional shallow impurity and DX is the displaced deep state. The superscripts specify the charge states, U the correction energy. Figure 2c below shows a configuration coordinate diagram of the Si DX center in AlN. The lowest parabola repr...
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