arXiv subjects

S. Suihkonen

Publications and source records attributed to S. Suihkonen.

3 recordsLinked to original sources

arXiv2018

N-polar AlN buffer growth by MOVPE for transistor applications

We present the electrical characterization of N-polar AlN layers grown by metal-organic vapor phase epitaxy and the demonstration of N-polar AlN-channel metal-semiconductor field-effect transistors (MESFETs). A high concentration of silicon is unintentionally incorporated during the high-temperature growth of N-polar AlN, causing high buffer leak current. The silicon concentration reduces from 2x10^18 /cm^3 to 9x10^15 /cm^3 with decreasing growth temperature, reducing the buffer leak current to 5.6 nA/mm at a 100 V bias. The N-polar AlN MESFET exhibits an off-state drain current of 0.27 nA/mm and a transistor on/off ratio of 4.6x10^4 due to the high-resistivity AlN buffer layers.

physics.app-ph↗

arXiv2018

MOVPE growth of N-polar AlN on 4H-SiC: effect of substrate miscut on layer quality

We present the effect of miscut angle of SiC substrates on N-polar AlN growth. The N-polar AlN layers were grown on C-face 4H-SiC substrates with a miscut towards <-1100> by metal-organic vapor phase epitaxy (MOVPE). The optimal V/III ratios for high-quality AlN growth on 1 deg and 4 deg miscut substrates were found to be 20000 and 1000, respectively. MOVPE grown N-polar AlN layer without hexagonal hillocks or step bunching was achieved using a 4H-SiC substrate with an intentional miscut of 1 deg towards <-1100>. The 200-nm-thick AlN layer exhibited X-ray rocking curve full width half maximums of 203 arcsec and 389 arcsec for (002) and (102) reflections, respectively. The root mean square roughness was 0.43 nm for a 2 um x 2 um atomic force microscope scan.

physics.app-ph↗

arXiv2018

MOVPE growth of nitrogen- and aluminum-polar AlN on 4H-SiC

We present a comprehensive study on metal-organic vapor phase epitaxy growth of N-polar and Al-polar AlN on 4H-SiC with 4 deg miscut using constant growth parameters. At a high temperature of 1165 degC, N-polar AlN layers had high crystalline quality whereas the Al-polar AlN surfaces had a high density of etch pits. For N-polar AlN, the V/III ratio below 1000 forms hexagonal hillocks, while the V/III ratio over 1000 yields step bunching without the hillocks. 1-um-thick N-polar AlN layer grown in optimal conditions exhibited FWHMs of 307, 330 and 337 arcsec for (002), (102) and (201) reflections, respectively.

physics.app-ph↗