Search

Vapor–liquid–solid (V–L–S) growth of SiC on (100) diamond substrate is reported. The crystalline quality is evaluated by transmission electron microscopy (TEM). Diffraction contrast (CTEM) observations allowed confirming the growth of fully lattice relaxed SiC 3C-type crystalline structure. Defects as dislocations at the diamond/SiC interface and stacking faults, in the thick SiC layer are revealed by high resolution TEM and CTEM. From the invisibility criteria, using dark field observations, 〈110〉 type Burger vector are identified.

We report the results of a series of LTPL (Low Temperature PhotoLuminescence) investigation performed on n-type, non-intentionally doped, 4H-SiC samples. We focus on the defect structure introduced by a growth fault in the stacking sequence. We treat the fault as a 3C quantum well embedded in a 4H-SiC matrix and use a simple 2-dimensional approximation to deduce the extent of the lattice perturbation associated with a given defect. We show that the intrinsic type-II nature of the band alignment, combined with the effect of the spontaneous polarization, must result in a double bound-exciton signature per well, which is resolved for the first time. The comparison with experimental results confirms also that, after a relatively small critical layer thickness, the back conversion from cubic to hexagonal remains an unsolved problem.

We report on the growth of thin, aluminium doped, homo-epitaxial layers of 4H-SiC using a threefold mixture of purified hexamethyldisilane (HMDS) admixted with propane (P) and trimethylaluminium (TMA). The growth has been performed in an AP-CVD, cold wall, vertical reactor in which the growth of 4H-SiC layers using HMDS admixed with propane has been well demonstrated. To control, as a function of the growth parameters, the amount of aluminium incorporated in the epitaxial layers SIMS, C(V) and Raman experiments were done. They show that good quality p-type epitaxial layers can be grown, up to a final aluminium concentration of about 2 x 10 19 at cm -3 . Comparing with the more standard gas system silane/TMA/P, we have found that there is no significant difference. The total amount of Al incorporated is about the same and, in both cases, the incorporation starts to be limited when the growth temperature reaches 1500 °C. In both cases, also, the C/Si ratio and the growth rate influence the aluminium concentration.

In order to process n-type channel MOSFETs on (1120)-oriented 4H-SiC wafers one has to optimise, independently, many different steps. First is the growth of the active epitaxial layer, including the effect of p-type doping. Next is the oxidation and, finally, the n-type implantation for source and drain formation. In this work, we investigate the growth and doping of the p-type doped epitaxial layer on the (1120)-oriented substrate using, both, SIMS, low temperature photoluminescence measurements and Hall effect measurement to control the final doping level. Next we investigate the change in oxidation kinetics with respect to the conventional (0001) surfaces. Finally, we evaluate the efficiency of implantation and annealing processes.