Three-dimensional epitaxial silicon microprobe array integrated on highly functional smart sensing chip

三维硅微探头与MOSFET电路集成在一起，用于与微电子学的电神经接口应用。在制作了硅(111)衬底的片上MOSFET后，我们提出了一种气-液-固(VLS)方法来实现微探针。我们研究了在Si(111)衬底上制作的片上MOSFET的特性。尽管Si(111)MOS系统中界面态密度的增加导致了MOFET的低性能，但我们通过后续的氟注入和长时间氢退火工艺改善了在Si(111)上的MOSFET的电学特性，表现出与在Si(100)衬底上相当的MOSFET的电学特性。VLS生长过程中的原位掺杂方法是一种利用低温工艺实现小于700℃的掺杂硅探针的可能性。分别用Ph_3或B_2H_6与Si_2H_6的硅气源混合，实现了n-型和p-型的硅探针。采用原位掺杂工艺生长的n型和p型硅探针均表现出低阻特性。尽管由于VLS生长的相同参数，上述VLS生长方法为探针阵列提供了相同的探针长度，但是在同一阵列中单独控制探针长度仍然是有问题的。为了实现不同长度的探针，我们还利用初步的VLS生长的微探针尖端残留的金的催化作用，重复地选择性地生长了硅微探针，从而得到了不同长度的探针。此外，我们已经实现了二氧化硅微管阵列和硅微探针阵列与MOSFET的集成，用于同时进行神经电记录和局部神经元组织的药物输送，该设备可能是一种高效的电/化学神经接口，可用于多种神经科学应用。

Three-dimensional silicon microprobes are integrated with MOSFET circuits for use in electrical neural interface applications with microelectronics. We have proposed a vapor-liquid-solid(VLS) method to realize microprobes after the fabrication of on-chip MOSFETs using Si(111) substrate. We investigated the characteristics of the on-chip MOSFETs fabricated on Si(111) substrate. Even though the increased interface state density in the Si(111) MOS system causes low-performance of the MOFET, we have improved the electrical characteristics of the MOSFETs on Si(111) using subsequent processes of fluorine implantation and long-time Hydrogen annealing, that exhibits comparable electrical characteristics of MOSFETs to that on Si (100)substrate. In-situ doping method during the VLS growth is one possibility to realize doped-silicon probes by low-temperature process with less than 700℃. We used PH_3 or B_2H_6 mixed with silicon gas source of Si_2H_6, in order to realize n- or p-type of silicon probes, respectively. Both n- and p-types of silicon probe grown by the in-situ doping process showed low electrical resistance characteristics. Although the above VLS growth method provides probe arrays with a same probe length due to same parameters of the VLS growth, individually controlled length of probe in a same array was still problematic. To realize the different lengths of probes, we also demonstrated a repeated selective VLS growth of silicon microprobes using the catalysis of gold remaining at the tip of a preliminary VLS-grown microprobe, resulting in different probe lengths. Additionally, we have realized the integration of silicon dioxide microtube arrays and the silicon micoroprobe arrays with MOSFETs, for use in simultaneous electrical neural recordings and drug delivery into local neuronal tissue, and this proposed device could be an efficient electrical/chemical neural interface for use in numerous neuroscience applications.