An AlN/Al0.85Ga0.15N high electron mobility transistor

Abstract

An AlN barrier high electron mobility transistor (HEMT) based on the AlN/Al0.85Ga0.15N heterostructure was grown, fabricated, and electrically characterized, thereby extending the range of Al composition and bandgap for AlGaN channel HEMTs. An etch and regrowth procedure was implemented for source and drain contact formation. A breakdown voltage of 810 V was achieved without a gate insulator or field plate. Excellent gate leakage characteristics enabled a high Ion/Ioff current ratio greater than 107 and an excellent subthreshold slope of 75 mV/decade. A large Schottky barrier height of 1.74 eV contributed to these results. The room temperature voltage-dependent 3-terminal off-state drain current was adequately modeled with Frenkel-Poole emission.

Ultrawide‐Bandgap Semiconductors: Research Opportunities and Challenges

“…[204] Further, a recent developmental AlN/Al 0.85 Ga 0.15 N HEMT has demonstrated n s = 6 × 10 12 cm −2 . [157] All of these devices are exceeded by about 3× or more in this category by the surface-transfer-doped diamond MOSFETs reported in the last column, many of which have shown credible high-frequency performance. [81,205] The fourth materials/device properties row reports electron drift mobility, where the best-known values for lowdoped materials are given.…”

“…[156] Electron mobilities in doped AlGaN layers approach hundreds of cm 2 V −1 s −1 , and are slightly higher in polarizationinduced 2DEGs. [54,66,157] Theoretically, electron and hole transport properties are likely to require fundamentally new concepts and approaches, because of the highly mismatched electronic properties of the binary constituents. For example, consider the AlInN material system.…”

Analysis of 2D Transport and Performance Characteristics for Lateral Power Devices Based on AlGaN Alloys

“…Here we take this to be a constant value of 10 13 cm −2 over the entire composition range, consistent with experimental reports on Al-rich AlGaN/AlGaN heterostructures. 4,5,7,9 Other authors have taken the approach that n s is proportional to E C , 18 which eliminates n s from the LFOM and makes it proportional to E C 3 rather than E C 2 . Thus, in such a situation the LFOM has the same dependence on critical field as the UFOM (UFOM = εμE C 3 /4 where ε is the dielectric constant of the semiconductor (F/cm) and μ is the bulk mobility).…”

“…In particular, a number of groups have demonstrated lateral transistors based on Al-rich AlGaN. [4][5][6][7][8][9] However, while the use of higher-bandgap AlGaN is expected to improve performance, exactly how much improvement and over what alloy and temperature ranges this improvement may be expected is unknown. Thus, this paper presents a theoretical analysis of the expected performance of lateral power switching devices.…”

High Temperature Operation of Al0.45Ga0.55N/Al0.30Ga0.70N High Electron Mobility Transistors

“…Previously published characteristics of AlGaN-channel HEMTs begin to lend support to these motivations. [8][9][10][11][12][13] In particular, the saturation drain current is reported to be relatively insensitive to temperature in AlGaN-channel HEMTs 9 and very favorable low leakage Schottky gate properties with very high drain current on-to-off ratios have been reported as well.13 * Electrochemical Society Member. z E-mail: agbaca@sandia.gov…”