Impact of in situ SiNx layer grown with metal organic vapor phase epitaxy on the electrical and optical properties of AlN/GaN metal insulator semiconductor field effect transistor structures

Abstract

AlN/GaN metal insulator semiconductor field effect transistor structures (MISFETs) with and without in situ SiNx were investigated. The in situ SiNx passivation layer was deposited using silane and ammonia immediately after the AlN/GaN heterostructure growth by metal organic vapor phase epitaxy. Superior Ohmic quality and improvement of the dc and rf characteristics were obtained with devices made on passivated layers in comparison with unpassivated devices. This enhancement of electrical characteristics is attributed to the fact that the in situ SiNx suppresses the depletion of the two-dimensional electron gas (2DEG) and air exposure while processing. The studies of the in situ SiNx quality and its implication to the 2DEG conducted with Hall, transmission line measurements, capacitance-voltage (C-V) measurements, and photoluminescence measurements showed that the electrical and optical characteristics of AlN MISFET structures were substantially degraded or changed after SF6 plasma treatment.

Low trap states in in situ SiNx/AlN/GaN metal-insulator-semiconductor structures grown by metal-organic chemical vapor deposition

“…[2][3][4][5][6] On the other hand, metal-insulator-semiconductor (MIS) structures are highly preferred over the Schottky-gate HEMTs due to the suppressed gate leakage current and enlarged gate swing. 3,[6][7][8][9][10][11][12][13][14][15][16][17][18] However, the insertion of a gate dielectric creates an additional dielectric/III-N interface with high-density traps typically in the range of 10 10 -10 14 cm À2 eV À1 . These defect states can substantially deteriorate the device performances.…”

“…6,16 However, the extra GaN layer between gate dielectric and AlN barrier is not preferable for a MIS device, because of the introduced additional GaN/AlN interface, the increased gate-to-channel distance and the relatively narrow bandgap of GaN. Although an in situ grown SiN x by MOCVD has been reported to be the optimum passivation layer for III-nitride HEMTs, 4,[17][18][19] interface trapping analysis for the in situ SiN x MIS structures is still limited. Recently, we also demonstrated the use of SiN x in situ grown by MOCVD as gate dielectrics and passivation for AlN/GaN MISHEMTs, 20,21 which show reduced gate leakage current and increased carrier concentration.…”

Fabrication and Characterization of Gate-Last Self-Aligned AlN/GaN MISHEMTs With <italic>In Situ</italic> SiN_{<italic>x</italic>} Gate Dielectric

“…The etch rate of in situ SiN x by BOE was found to be extremely slow [31], which is attributed to the high growth temperature (1145°C) in our experiment. We observed no obvious degradation on the in situ SiN x surface even after a 10-min immersion in the BOE.…”

In Situ Interferometry of MOCVD-Grown ZnO for Nucleation-Layer-Based Optimization and Nanostructure Formation Monitoring

“…However, in situ interferometry techniques have rarely been used for optimization of MOCVD-grown ZnO. [33][34][35][36] This paper reports optimization of high-temperature (HT) ZnO layers grown on c-plane GaN layers by studying the impact of nucleation layer (NL) thickness. The impact of growth temperature on the formation of ZnO nanostructures on top of (100) silicon substrates is also studied by means of in situ interferometry.…”