Limits...
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

TEM images of the oxidized sample. Bright field TEM analysis (a) and EFTEM (b) for oxygen on a sample oxidized by RTA at 900°C for 10 min.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3211179&req=5

Figure 5: TEM images of the oxidized sample. Bright field TEM analysis (a) and EFTEM (b) for oxygen on a sample oxidized by RTA at 900°C for 10 min.

Mentions: Figure 5 shows the TEM images of the oxidized sample. Combining the bright field image (a) with the oxygen map acquired by EFTEM (energy-filtered transmission electron microscopy) analysis (b) allowed to demonstrate the presence of a surface oxide layer of a thickness of about 2 nm grown after the process at 900°C. Previous experiments on long-term oxidation have shown the formation of a mixed oxide of Al2O3 - Ga2O3 with a high chemical stability with respect to wet etching [11].


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)

TEM images of the oxidized sample. Bright field TEM analysis (a) and EFTEM (b) for oxygen on a sample oxidized by RTA at 900°C for 10 min.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 5: TEM images of the oxidized sample. Bright field TEM analysis (a) and EFTEM (b) for oxygen on a sample oxidized by RTA at 900°C for 10 min.
Mentions: Figure 5 shows the TEM images of the oxidized sample. Combining the bright field image (a) with the oxygen map acquired by EFTEM (energy-filtered transmission electron microscopy) analysis (b) allowed to demonstrate the presence of a surface oxide layer of a thickness of about 2 nm grown after the process at 900°C. Previous experiments on long-term oxidation have shown the formation of a mixed oxide of Al2O3 - Ga2O3 with a high chemical stability with respect to wet etching [11].

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