![]() Therefore, although p-channel metal-semiconductor FET (MESFET) has been reported by using InGaN/GaN heterostructure, its performances such as leakage current, drain-source current density (0.01 mA/mm), ON/OFF ratio remain still quite poor 25. However, it is still difficult to experimentally extract high-density 2DHG in the InGaN system. It has been theoretically simulated that for the compressively strained InGaN layer on the relaxed GaN template, holes can be confined close to the lower interface as a result of the dominant piezoelectric polarization field 22, 23, 24, 25, 26. ![]() Moreover, InGaN presents higher piezoelectric polarization coefficient compared to its III-nitrides rivals, which is beneficial for the generation and accumulation of high density 2DHG in conducting channel 21. In addition, the adjustable compressive strain in InGaN increases the deformation of valence bands and splits the degeneracy between light hole and heavy hole bands 19, which also enhances the hole mobility 20. Compared to the AlGaN system, InGaN offers a better route for the p-channel transistors in term of a much lower on-resistance because of its lower activation energy of Mg dopants and hole effective mass 17, 18. The 2DHG and related p-channel FETs have been proposed in Al(Ga)N- and AlInGaN-based heterostructure 12, 13, 14, 15, 16. The unbalanced development between n-channel and p-channel FETs makes the complementary ICs using III-Nitrides a great challenge, implying that the research on III-Nitrides p-channel FETs is in great demand.Īccording to the polarization theory, two-dimensional hole gas (2DHG) with high charge density and high mobility can be induced by negative polarization charge at the III-Nitrides heterointerface similarly to that for 2DEG 6, 7, 8, 9, 10, 11. ![]() On the other hand, little attention has been paid to p-channel FETs because of the difficulty in obtaining hole with high charge density and high mobility. Recently, III-Nitrides n-channel heterojunction FETs using polarization-induced two-dimensional electron gas (2DEG) have already been extensively investigated with lower specific on-resistance and higher electron mobility compared with those of Si-based FETs 5. To achieve the complementary ICs, both n- and p-channel field effect transistors (FETs) with well-matched performance are necessary 4. Wide-bandgap semiconductor III-Nitrides provide a better choice for the logic ICs applications owing to their superior physical and chemical properties, such as the high breakdown voltage, high thermal stability, large saturation velocity and high carrier mobility at heterojunctions 2, 3. The conventional Si-based complementary logic integrated circuits (ICs) show the drawbacks of large leakage current and poor reliability in harsh environments 1. ![]()
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