Based On Porous Silicon Biosensor Principle

Since Canham discovered the room-temperature highly-efficient luminescence of visible light from Porous silicon (PS) in 1990, a large number of studies have been devoted to understand all aspects of PS, including basic theory, processing technology, applications widening, etc. PS has many unique properties such as enormous internal surface, high resistance ratio, high chemical activity, etc, praised as "quantum sponge". PS has been developed in many application fields including optoelectronics, microwave/radio frequency microelectronics, sensor, biomedicine, etc. This dissertation focused on studing applications of PS in DNA chip, potassium ion selective microelectrode (K+ISME) and Hydroxyapatite (HAP) coating and also some results have been achieved as follows:Selective PS has been successfully obtained. Both Au/Cr film (2000A) deposited on silicon wafer and highly resistive silicon film (1um) formed by hydrogen ion implantation (50Kev) can be used as masks to produce PS microarrays with good integrity and distribution by selective electrochemical etching process.PS was first used as the substrate to fabricate DNA chip. Some primary experiment results have been achieved. One China invention patent has been applied. The attachment rate of oligonucleotide on PS is increased with the pore diameter. Detection sensitivity of DNA chip based on PS is higher than that based on glass. Also DNA chip based on PS is stable under 4 storage conditions.A PS-based K+ISME with a good performance has been firstly fabricated. The calibration curve for the K+ISME is linear within a wide range of pK = 1.0 ~ 4.0. Its slope is 56 mV per decade, which is near Nernst response. The long-term stability of the K+ISME is good. The variation of the response is within ?2 mV during 2 months.HAP has been successfully prepared by sol-gel method. HAP(20um) was successfully coated on PS substrate. It was found that rapid thermal annealing (RTA) process is able to enhance crystallinity of HAP. And the thermal treatment at 1000C conglutinates the HAP layer tightly with the PS substrate. That will benefit implantation of sensors and IC in human bodies so as to reduce and even entirely avoid biological rejection.