High-yield growth of p-Si microprobe arrays by selective vapor-liquid-solid method using in situ doping and their properties

Au-catalyzed selective vapor-liquid-solid (VLS) growth using in situ doping with the gas source of Si2H6 and B2H6 has been used to realize p-type Si-microprobe array with very high yield and the properties of these p-Si microprobes have been investigated in this work. VLS growth using Si2H6 only gives intrinsic Si microprobes, which could be doped by diffusion process (at 1100 °C) after VLS growth. But incorporating in situ doping using the mixed gas of Si2H6 and B2H6 with VLS growth process, doped p-Si microprobes can be realized directly at a temperature (less than 700 °C) lower than that required at diffusion process. The diameter and length of these microprobes can be selectively controlled by forming Au dots with desired size and thickness at the desired position along with the tuning of the growth conditions and time. The effects of boron doping on the growth rate and the electrical properties of these p-Si microprobes are investigated. Due to low-temperature processing, in situ doping approach is compatible to realize doped p-Si microprobe array with on-chip circuitry to develop smart chips for sensor applications. Also this study of p-probe properties would be useful while realizing vertical active devices like diodes, transistors, etc. with p-Si microprobes.