Investigation of giant step bunching in 4H-SiC homoepitaxial growth: Proposal of cluster effect model

Abstract

We have investigated the H 2 etching and growth conditions causing giant step bunching (GSB) in 4H-SiC homoepitaxial growth on 8°off-axis substrates by a chemical vapor deposition method and found that GSB does not occur during H 2 etching under a wide range of experimental conditions, whereas GSB occurs during epitaxial growth at extremely low or high C/Si ratios, i.e., an excessive supply of SiH 4 or C 3 H 8 . To explain these results, we have proposed a model taking into account the effect of Si or C cluster formation called "the cluster effect" model. We have shown that the cluster effect model can explain well our experimental result of GSB occurrence or nonoccurrence during etching and homoepitaxial growth of 4H-SiC.

Investigation of the giant step bunching induced by the etching of 4H-SiC in Ar–H2 mix gases

“…[1][2][3] Step bunching is classified into one of two types on the basis of the step height. 4) One type is less than or equal to one unit crystal cell and the other is greater than one unit cell in height. We call the former normal step bunching (NSB) and the latter giant step bunching (GSB).…”

“…[8][9][10][11][12] In the case of GSB, the terrace with a width more than 200 nm can be formed. 2,4,[13][14][15][16] Because the integration densities of the most advanced LSI are sub-billion transistors per cm 2 in terms of the order of magnitude, the transistor interval should be more than several hundred nm. Therefore, GSB is considered suitable as the template for the integration of nanodevices.…”

“…On the basis of these results, we have proposed the mechanism of the generation of GSB taking into account the effect of silicon (Si) or carbon (C) cluster formation; the mechanism is thus called "the cluster effect" model. 4) The cluster effect is as follows. The concentration of Si or C clusters formed by an excessive supply of source gases depends on terrace width.…”

Fabrication of 4H-SiC lateral double implanted MOSFET on an on-axis semi-insulating substrate without using epi-layer

“…12) However, step bunching often occurs during the epitaxial growth and high temperature activation process. 13) The step bunching makes surface rough 14) and causes scattering of carriers at the surface. Consequently, the channel mobility of the MOSFET is dramatically reduced.…”

Proposal of the mechanism for inclination growth on a mesa top during the 4H-SiC trench filling epitaxy

“…We have studied the etching and homoepitaxial growth of SiC and elucidated theoretically their mechanisms. [23][24][25][26][27][28][29] In this communication, we examine the inclination growth phenomena in the trench filling based on the homoepitaxial growth of SiC, i.e., growth on an off-angled substrate surface, and attempt to determine the relationship between the misalignment angle of the trench direction and the inclination growth angle of the epilayer on the mesa top.…”