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Near-surface processing on AlGaN/GaN heterostructures: a nanoscale electrical and structural characterization.

Greco G, Giannazzo F, Frazzetto A, Raineri V, Roccaforte F - Nanoscale Res Lett (2011)

Bottom Line: In particular, a CHF3-based plasma process in the gate region resulted in a shift of the threshold voltage in HEMT devices towards less negative values.Two-dimensional current maps acquired by C-AFM on the sample surface allowed us to monitor the local electrical modifications induced by the plasma fluorine incorporated in the material.The results are compared with a recently introduced gate control processing: the local rapid thermal oxidation process of the AlGaN layer.By this process, a controlled thin oxide layer on surface of AlGaN can be reliably introduced while the resistance of the layer below increase locally.

View Article: PubMed Central - HTML - PubMed

Affiliation: Consiglio Nazionale delle Ricerche - Istituto per la Microelettronica e Microsistemi (CNR-IMM), Strada VIII n, 5, Zona Industriale, 95121 Catania, Italy. fabrizio.roccaforte@imm.cnr.it.

ABSTRACT
The effects of near-surface processing on the properties of AlGaN/GaN heterostructures were studied, combining conventional electrical characterization on high-electron mobility transistors (HEMTs), with advanced characterization techniques with nanometer scale resolution, i.e., transmission electron microscopy, atomic force microscopy (AFM) and conductive atomic force microscopy (C-AFM). In particular, a CHF3-based plasma process in the gate region resulted in a shift of the threshold voltage in HEMT devices towards less negative values. Two-dimensional current maps acquired by C-AFM on the sample surface allowed us to monitor the local electrical modifications induced by the plasma fluorine incorporated in the material.The results are compared with a recently introduced gate control processing: the local rapid thermal oxidation process of the AlGaN layer. By this process, a controlled thin oxide layer on surface of AlGaN can be reliably introduced while the resistance of the layer below increase locally.

No MeSH data available.


Related in: MedlinePlus

Schematic representations. Schematic representations of an untreated HEMT device (a) and of a HEMT subjected to CHF3 plasma processing (b). IDS-VDS characteristics of HEMT device not subjected to the plasma treatment (squares) and subjected to the plasma treatment and to an annealing (triangles).
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Figure 1: Schematic representations. Schematic representations of an untreated HEMT device (a) and of a HEMT subjected to CHF3 plasma processing (b). IDS-VDS characteristics of HEMT device not subjected to the plasma treatment (squares) and subjected to the plasma treatment and to an annealing (triangles).

Mentions: In Figure 1a, a schematic of a typical HEMT device is reported, in which the location of the 2DEG at the interface between GaN and the AlGaN barrier layer is reported. The current flow between the source and drain Ohmic contacts is controlled modulating the 2DEG carrier concentration in the channel region through the bias applied to the gate Schottky contact on the AlGaN barrier layer.


Near-surface processing on AlGaN/GaN heterostructures: a nanoscale electrical and structural characterization.

Greco G, Giannazzo F, Frazzetto A, Raineri V, Roccaforte F - Nanoscale Res Lett (2011)

Schematic representations. Schematic representations of an untreated HEMT device (a) and of a HEMT subjected to CHF3 plasma processing (b). IDS-VDS characteristics of HEMT device not subjected to the plasma treatment (squares) and subjected to the plasma treatment and to an annealing (triangles).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211179&req=5

Figure 1: Schematic representations. Schematic representations of an untreated HEMT device (a) and of a HEMT subjected to CHF3 plasma processing (b). IDS-VDS characteristics of HEMT device not subjected to the plasma treatment (squares) and subjected to the plasma treatment and to an annealing (triangles).
Mentions: In Figure 1a, a schematic of a typical HEMT device is reported, in which the location of the 2DEG at the interface between GaN and the AlGaN barrier layer is reported. The current flow between the source and drain Ohmic contacts is controlled modulating the 2DEG carrier concentration in the channel region through the bias applied to the gate Schottky contact on the AlGaN barrier layer.

Bottom Line: In particular, a CHF3-based plasma process in the gate region resulted in a shift of the threshold voltage in HEMT devices towards less negative values.Two-dimensional current maps acquired by C-AFM on the sample surface allowed us to monitor the local electrical modifications induced by the plasma fluorine incorporated in the material.The results are compared with a recently introduced gate control processing: the local rapid thermal oxidation process of the AlGaN layer.By this process, a controlled thin oxide layer on surface of AlGaN can be reliably introduced while the resistance of the layer below increase locally.

View Article: PubMed Central - HTML - PubMed

Affiliation: Consiglio Nazionale delle Ricerche - Istituto per la Microelettronica e Microsistemi (CNR-IMM), Strada VIII n, 5, Zona Industriale, 95121 Catania, Italy. fabrizio.roccaforte@imm.cnr.it.

ABSTRACT
The effects of near-surface processing on the properties of AlGaN/GaN heterostructures were studied, combining conventional electrical characterization on high-electron mobility transistors (HEMTs), with advanced characterization techniques with nanometer scale resolution, i.e., transmission electron microscopy, atomic force microscopy (AFM) and conductive atomic force microscopy (C-AFM). In particular, a CHF3-based plasma process in the gate region resulted in a shift of the threshold voltage in HEMT devices towards less negative values. Two-dimensional current maps acquired by C-AFM on the sample surface allowed us to monitor the local electrical modifications induced by the plasma fluorine incorporated in the material.The results are compared with a recently introduced gate control processing: the local rapid thermal oxidation process of the AlGaN layer. By this process, a controlled thin oxide layer on surface of AlGaN can be reliably introduced while the resistance of the layer below increase locally.

No MeSH data available.


Related in: MedlinePlus