Effect of Al vacuum annealing prior to a‐Si deposition on aluminum‐induced crystallization

Abstract

Aluminum-induced crystallization (AIC) experiments were carried out in order to investigate the influence of vacuum annealing of the Al layer at 500 8C prior to deposition of e-beam evaporated amorphous silicon (a-Si). A control sample set using the identical deposition sequences but without the Al vacuum anneal was also produced as reference. Analysis revealed that after vacuum annealing, the Al grain size increases significantly. The surface Aloxide layer thickness is reduced, however, the Al-oxide to metallic Al ratio is increased in this layer. Following a-Si deposition, the a-Si/Al/SiN x /glass stacked samples were annealed in N 2 atmosphere at temperatures between 420 and 450 8C. It was seen that the crystal growth rate in the samples with vacuum-annealed Al is significantly reduced compared to the control samples, due to the reduction of Al grain boundary density.

Metal-induced layer exchange of group IV materials

“…These effects depend on the metal species, which reflects the deference of the screening effect, diffusion rate and interfacial energies [14,17,96]. The crystallization temperature can be also lowered (that is, LE can be facilitated) by: (i) controlling the semiconductor/metal interlayer [58,100,101], (ii) tuning the grain size of the metal layer [102][103][104], (iii) modulating the substrate surface condition [105], (iv) initial semiconductor doping in the metal layer [27,106,107], (v) applying eternal voltage during annealing [108] and (vi) introducing defects [109] or impurities [110][111][112] into the amorphous semiconductor layer.…”

“…Thin film preparation also contributes to large grain growth because the thinner metal layer requires greater lattice diffusion of semiconductor atoms in addition to grain boundary diffusion, which delays nucleation [96]. The metal grain size, that is the grain boundary density, affects the grain size of the resulting semiconductor layer because it changes the diffusion rate of the semiconductor atoms into the metal [102][103][104]. Higashi et al improved the lateral diffusion rate and induced large grain growth in the Ge-Au system by preparing a thin multilayer structure of Ge and Au (figure 7(d)) [99].…”

Applications of 2D-Layered Palladium Diselenide and Its van der Waals Heterostructures in Electronics and Optoelectronics

“…Remarkably, vacuum annealing is an effective method for improving the mobility of FETs, and it has been widely used in electronic devices [ 72 ]. For PdSe 2 FETs, annealing can remove the surface adsorbates to achieve higher mobility, on/off ratio, and lower Schottky barrier.…”

Layer exchange synthesis of multilayer graphene

“…The qualities of the initial carbon and metal layers are also important factors. Because the carbon atoms diffuse mainly through metal grain boundaries, a metal layer with smaller grains will induce a faster rate (lower growth temperature) of LE [116][117][118]. Introducing defects [119] or impurities [120,121] into the a-C layer will also make the carbon bonds in a-C easier to break and promote diffusion of carbon atoms into metals.…”