Negative differential resistance in GaN homojunction tunnel diodes and low voltage loss tunnel contacts
The current-voltage characteristics and metastability in GaN p++/n++ homojunction tunnel diodes and n++/p++/i/n tunnel-contacted diodes grown via metal modulated epitaxy have been investigated. The room temperature negative differential resistance (NDR) beginning at ∼1.35 V is reported for GaN homoj...
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Veröffentlicht in: | Applied physics letters 2018-06, Vol.112 (25) |
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Sprache: | eng |
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Zusammenfassung: | The current-voltage characteristics and metastability in GaN p++/n++ homojunction tunnel diodes and n++/p++/i/n tunnel-contacted diodes grown via metal modulated epitaxy have been investigated. The room temperature negative differential resistance (NDR) beginning at ∼1.35 V is reported for GaN homojunction devices grown on sapphire. The NDR vanishes, and the conductivity increases as multiple I-V sweeps are performed, thus suggesting that charge trapping states with long trap lifetimes exist at defect sites, and these traps play a crucial role in the tunneling mechanism. Additionally, the use of extremely high n-type (ND ∼ 4.6 × 1020 cm−3) and p-type (NA ∼ 7.7× 1020 cm−3) doping results in a near linear characteristic with minimal rectification at current densities less than 200 A/cm2 and soft rectification above this current density. Forward-bias tunneling and NDR are still present at 77 K. The highest silicon-doped n++/p++/i/n tunnel-contacted pin diode demonstrates a turn-on voltage of 3.12 V, only 0.14 V higher than that of the pin control diode, and an improved specific on-resistance of 3.24 × 10−4 Ω cm2, which is 13% lower than that of the control pin diode. |
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ISSN: | 0003-6951 1077-3118 |
DOI: | 10.1063/1.5035293 |