Selective Epitaxial Growth of Silicon for Vertical Diode Application

Abstract

Selectivity control in silicon selective epitaxial growth (SEG) for deep contact patterns, which is one of the key processes for silicon-based stacked devices and cell switches for next generation memories, was studied. Absolute values of selectivity loss during silicon SEG using the most popular H 2 /dichlorosilane (DCS)/HCl gas system were evaluated using a commercialized inspection tool in 200 mm wafers with real contact patterns. It was revealed that HCl=ðDCS þ HClÞ ratio and the contact structure played a crucial role in suppressing selectivity loss. The number of selectivity losses in an entire wafer was less than 100 when the HCl=ðDCS þ HClÞ ratio was larger than 0.41. The vertical pn diode prepared using the silicon SEG process with elaborate selectivity control showed more remarkable electrical abilities to accommodate current flow than polycrystalline silicon (poly-Si), including the ideality factor and swing, and reverse leakage current.

Flexible One Diode-One Phase Change Memory Array Enabled by Block Copolymer Self-Assembly

“…It should be noted that the pulse current of the f-BPCM device measured from voltage pulse for RESET/SET operations (inset of Figure c) was effectively blocked at the reverse bias by the introduction of the intrinsic region between the P- and N-doping areas to keep the rectifying capability even at the high reverse voltage. Laterally structured PN diodes can be converted into high performance vertical diode structures by incorporation of well-controlled ion implantation or epitaxial silicon growth for high-density 1D-1P structures. − The R – V characteristics of the flexible 1D-1P unit cell in the pulse mode and the corresponding circuit diagram are shown in Figure d. The electrical properties of the 1D-1P unit cell were evaluated in conditions equivalent to those of the f-BPCM, and the resistance values were measured to be higher than those of the f-BPCM device without the diode.…”

Highly manufacturable silicon vertical diode switches for new memories using selective epitaxial growth with batch-type equipment

“…Those research works have employed vertical diodes for switching devices in order to replace the conventional metaloxide-semiconductor field effect transistors (MOSFETs). We also reported that selectively grown silicon (SEG-Si) showed superior electrical performance to polycrystalline silicon (poly-Si) for the diode application [18]. It must be pointed out that the selectivity window is somewhat tolerable for the application to elevated source/drain or strain engineering; Nakano et al even reported the deposition of poly-Si during ESD formation [19].…”

“…Selectivity loss was counted for the samples with SEG-Si after the separation of silicon nodes. Process conditions for pattern wafers were published elsewhere [18,25].…”