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Research in Organic Permeable Base Transistors (OPBTs) has led to a significant increase in their performance. However, despite this progress, understanding of the working mechanism of OPBTs is still limited. Although first numerical models of OPBTs are able to describe the switching mechanism of OPBTs correctly, they neglect currents injected at the base electrode, which leads to unrealistically low off-currents and high ON/OFF ratios. Here, a tunneling model is developed that is capable of describing injection of charges through a thin oxide layer formed around the base electrode of OPBTs. With the help of this injection model, the performance of the base-collector diode of OPBTs is discussed. In particular, the model is used to explain the reduction in backward currents due to an exposure to ambient air by an increase in the thickness of the oxide layer. Furthermore, the tunnel model is used to show that the reduction in backward currents of the base-collector diode leads to a decrease in off-currents of complete OPBTs, which in turn leads to an increase in their ON/OFF ratio.
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Stability of organic permeable base transistors
Organic Permeable Base Transistors (OPBTs) reach a very high transit frequency and large on-state currents. However, for a later commercial application of this technology, a high operational stability is essential as well. Here, the stability of OPBTs during continuous cycling and during base bias stress is discussed. It is observed that the threshold voltage of these transistors shifts toward more positive base voltages if stressed by applying a constant potential to the base electrode for prolonged times. With the help of a 2D device simulation, it is proposed that the observed instabilities are due to charges that are trapped on top of an oxide layer formed around the base electrode. These charges are thermally released after removing the stress, and the device reaches its initial performance after around 24–48 h.
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- Award ID(s):
- 1639073
- PAR ID:
- 10161125
- Date Published:
- Journal Name:
- Applied physics letters
- Volume:
- 115
- ISSN:
- 1520-8842
- Page Range / eLocation ID:
- 193301
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1063/1.5125233
