Realization of in situ doped n-type and p-type Si-microprobe array by selective vapor-liquid-solid (VLS) growth method

In this paper we report the development of n-type and p-type Si-microprobe arrays fabricated by using in situ doping in vapor-liquid-solid, (VLS) growth employing a gas-source molecular beam epitaxy (GS-MBE) system as the growth environment. VLS growth using Si2H6 only gives intrinsic Si microprobes with the resistivity of similar to 10(4) Omega-cm, which decreases to similar to 10-(2) Omega-cm after phosphorous diffusion at 1100 degrees C. However, by incorporating in situ doping into the VLS growth method, more conductive probes (resistivity similar to 10(-3) Omega-cm) can be realized at a temperature less than 700 degrees C. The site and diameter of the VLS-grown probe can be controlled and the growth rate is higher than that of a poly-Si or epitaxial Si crystal grown by the vapor-solid (VS) method. Due to the low processing temperature, in situ doping is effective for realizing highly conductive probe arrays with smart sensor devices by a standard IC process followed by VLS growth. The wide range of doping leads to the possibility of using these probes for the fabrication of vertical active devices such as diodes and transistors.