Influence of phosphorus diffusion modes on the formation of defects in an oxide

Using optical microscopy, SEM, atomic force microscope and profilometer, the shape, size and impurity composition of local defects occurring in the silicon dioxide layer during phosphorus diffusion were determined. The reason for the formation of defects in the passivating oxide during phosphorus diffusion is the local melting of SiO2 in interaction with liquid drops of phosphoric-silicate glass. A decrease in the temperature of the phosphorus deposition process and the concentration of POCL3 in the gas stream leads to a decrease in the density of oxide defects.

Research on Sapphire Deep Cavity Corrosion and Mask Selection Technology

Aimed at the problem of the small wet etching depth in sapphire microstructure processing technology, a multilayer composite mask layer is proposed. The thickness of the mask layer is studied, combined with the corrosion rate of different materials on sapphire in the sapphire etching solution, different mask layers are selected for the corrosion test on the sapphire sheet, and then the corrosion experiment is carried out. The results show that at 250 °C, the choice is relatively high when PECVD (Plasma Enhanced Chemical Vapor Deposition) is used to make a double-layer composite film of silicon dioxide and silicon nitride. When the temperature rises to 300 °C, the selection ratio of the silicon dioxide layer grown by PECVD is much greater than that of the silicon nitride layer. Therefore, under high temperature conditions, a certain thickness of silicon dioxide can be used as a mask layer for deep cavity corrosion.

Положительный заряд в КНС-гетероструктурах с межслойным оксидом кремния

The continuous transfer of (001)Si layers 0.2–1.7 μm thick by implanted hydrogen to the c -sapphire surface during direct bonding at high temperatures of 300–500°C is demonstrated for the first time. The formation of an intermediate silicon-oxide layer SiO_ x during subsequent heat treatments at 800–1100°C, whose increase in thickness (up to 3 nm) correlates with an increase in the positive charge Q _ i at the heterointerface to ~1.5 × 10^12 cm^–2 in contrast to the negative charge at the SiO_ x /Al_2O_3 ALD heterointerface. During silicon-layer transfer to sapphire with a thermal silicon-dioxide layer, Q _ i decreases by more than an order of magnitude to 5 × 10^10 cm^–2 with an increase in the SiO_2 thickness from 50 to 400 nm, while the electron and hole mobilities barely differ from the values in bulk silicon. Based on these results, a qualitative model of the formation of positively charged oxygen vacancies in a 5-nm sapphire layer near the bonding interface is proposed.