Hydrogen iodide (HI) neutral beam etching characteristics of InGaN and GaN for micro-LED fabrication.

We investigated the etching characteristics of hydrogen iodide (HI) neutral beam etching (NBE) of GaN and InGaN and compared with Cl2NBE. We showed the advantages of HI NBE versus Cl2NBE, namely: higher InGaN etch rate, better surface smoothness, and significantly reduced etching residues. Moreover, HI NBE was suppressed of yellow luminescence compared with Cl2plasma. InClxis a product of Cl2NBE. It does not evaporate and remains on the surface as a residue, resulting in a low InGaN etching rate. We found that HI NBE has a higher reactivity with In resulting in InGaN etch rates up to 6.3 nm min-1, and low activation energy for InGaN of approximately 0.015 eV, and a thinner reaction layer than Cl2NBE due to high volatility of In-I compounds. HI NBE resulted in smoother etching surface with a root mean square average (rms) of 2.9 nm of HI NBE than Cl2NBE (rms: 4.3 nm) with controlled etching residue. Moreover, the defect generation was suppressed in HI NBE compared to Cl2plasma, as indicated by lower yellow luminescence intensity increase after etching. Therefore, HI NBE is potentially useful for high throughput fabrication ofµLEDs.

Modulation of the coordination geometries of NCN and NCNC Rh complexes for ambidextrous chiral catalysts.

A chirality switch between novel NCN pincer Rh complexes and a related double cyclometalated NCNC Rh complex containing secondary amino groups is described. Their catalytic abilities were determined in asymmetric alkynylation of ethyl trifluoropyruvate, and the change in the coordination geometry of the Rh catalysts affected the stereochemistry of the products.

Collection of DICOM RDSR (Digital Imaging and Communication in Medicine, Radiation Dose Structured Report) Information Aimed at Reducing Patient Exposure Dose.

The recent progress in angiography technology bestows benefits on patients for minimally invasive than surgery, while there has been an increase in the number of cases involving stochastic effects, such as radiation dermatitis, resulting from upgrading of the procedure because of an extension of the time for fluoroscopy and the number of shots. Recent CT equipment saves the dose data along with image data about the information management for patient exposure dose, which is used for management of individual cumulative dose and the presumed effective dose, using digital imaging and communication in medicine (DICOM). We extracted detailed information about shooting conditions and dose from the DICOM radiation dose structured report (DICOM RDSR) in the angiography area, and evaluated the trend of patient exposure dose in each procedure. As a result, we found that cases exceeding 3 Gy which needed observation in the head region were 16.7% and in the heart region were 27.3%. We also found that angiography had a higher dose of shooting than did fluoroscopy, and that the diagnosis and treatment with tumor involvement required a exposure dose than did vascular lesion. In this paper, we review the shooting conditions as a root of DICOM RDSR information and consider the possibility of planning for further reduction of the exposure dose.