High-current-density thin-film silicon diodes grown at low temperature

Abstract

High-performance thin-film silicon n–i–p diodes are fabricated at temperatures below 160°C using hot-wire chemical vapor deposition. The 0.01mm2 diodes have a forward current-density of near 1000A∕cm2 and a rectification ratio over 107 at ±2V. Use of microcrystalline silicon i and n layers results in higher current-density diodes than with amorphous silicon, primarily by lowering a barrier to carrier injection. A 30nm intrinsic Si buffer layer between the i and p layers is needed to reduce the reverse leakage current. Minimizing diode area increases forward current density by reducing the voltage drop across the external series resistances.

High‐Current‐Density CuO x/InZnOx Thin‐Film Diodes for Cross‐Point Memory Applications

“…However, it is difficult to use epitaxial or polycrystalline-silicon-based p-n diodes for 3D stack structures owing to high processing temperatures, significant costs, and the possible formation of silicide on a metallic layer. [5] Amorphous hydrogenated silicon (a-Si:H)-based diodes have been also investigated; [7,8] however, their current density was rather low (<10 3 A cm À2 ) owing to the large bulk resistance. Therefore, we require new p-n diodes with low processing temperatures and high performance.…”

Amorphous silicon memory arrays

“…The high current density is needed to insure that a 0.1 lm · 0.1 lm device passes the microamps of current needed to write the memory element. Diodes capable of these high current densities with low off-currents require special fabrication structures, i.e., a composite lc-Si/a-Si:H sandwich structure [2]. The diode forward current is dominated by the n + -layer doping and the mobility of the carriers near the n + /i interface.…”

“…The predominant alternative in the market is the flash memory which provides a high density but is a rather expensive nonvolatile memory system (40 GBytes is approximately $2000). The cost arises from (1) the per wafer processing costs associated with the multi-billion dollar fabrication facilities capable of 0.1 lm features, (2) the testing and packaging costs. Both the Si wafer processing costs and Si material costs are unlikely to continue to show significant cost reductions as in the past.…”

Write-once diode/antifuse memory element with a sol-gel silica antifuse cured at low temperature

“…Recently, high-performance thin-film silicon p-i-n diodes were deposited at temperatures as low as 160 C, using a combination of hydrogenated amorphous silicon (a-Si:H) and microcrystalline silicon layers [5]. The 180-i-layer is incorporated to reduce reverse tunneling currents between the highly defective doped layers, as in normal a-Si:H diode structures.…”

“…The thin microcrystalline silicon n-i-p diode is fabricated by hot-wire chemical vapor deposition (HWCVD) onto an 80-nm Cr-coated glass substrate at 160 C. The thickness of n-, i-, and p-layers are 20, 180, and 30 nm, respectively. Details of the thin-film Si diode structure, fabrication, and characterization are published elsewhere [5]. The antifuse layer is a silica film made by spin-coating from a commercial "spin-on glass" solution in denatured alcohol (Silicafilm, Emulsitone Co., NJ).…”