Monolithic nuclear event detector and method of manufacture
View Patent ↗A PIN diode-based monolithic Nuclear Event Detector and method of manufacturing same for use in detecting a desired level of gamma radiation, in which a PIN diode is integrated with signal processing circuitry, for example CMOS circuitry, in a single thin-film Silicon On Insulator (SOI) chip. The PIN diode is implemented in the p-substrate layer. The signal processing circuitry is located in a thin semiconductor layer and is in electrical communication with the PIN diode. The PIN diode may be integrated with the signal processing circuitry onto a single chip, or may be fabricated stand alone using SOI methods according to the method of the invention.
1. A method of manufacturing a PIN diode in a Silicon On Insulator (SOI) substrate, comprising the steps of:
obtaining a semiconductor structure comprising a p − type substrate having a top and bottom surface, a buried oxide layer having a top and bottom surface, and an active silicon layer having a top and bottom surface, in which said top surface of said p − type substrate is in contact with said bottom surface of said buried oxide layer and said top surface of said buried oxide layer is in contact with said bottom surface of said active silicon layer;
depositing a first photoresist layer upon said top surface of said active silicon layer in a desired pattern;
etching said active silicon layer to form a first aperture for an anode region and a second aperture for a cathode region;
stripping said first photoresist layer;
applying a first applied layer of silicon dioxide to an upper surface of the resulting structure having a top surface and a bottom surface;
applying a second photoresist layer upon said top surface of said first applied layer of silicon dioxide in said desired pattern;
etching said first applied silicon dioxide layer to expose said top surface of said p − type substrate in said anode region and said cathode region;
stripping said second photoresist layer;
applying a third photoresist layer upon an upper surface of the resulting structure;
implanting a p+ region in said exposed top surface of said p− type substrate in said anode region;
stripping said third photoresist layer;
applying a fourth photoresist layer upon said upper surface of the resulting structure;
implanting an n+ region in said exposed top surface of said p − type substrate in said cathode region;
stripping said fourth photoresist layer;
depositing a metal layer upon an upper surface of the resulting structure; and
applying a fifth photoresist layer upon said upper surface of the resulting structure;
etching unwanted metal from said metal layer in a desired pattern to form a first metallic anode contact in electrical communication with said anode region thereby creating a PIN diode anode contact, and to form a second metallic cathode contact in electrical communication with said cathode region, thereby creating a PIN diode cathode contact; and
stripping said fifth photoresist layer.
2. The method of claim 1 in which said desired pattern is an interdigitated pattern.
3. The method of claim 2 further comprising the step of passivating.
4. The method of claim 2 further comprising the step of creating signal processing circuitry in said active silicon layer, said signal processing circuitry being in electrical communication with said PIN diode anode contact and said PIN diode cathode contact.
5. The method of claim 1 in which said desired pattern is a linear pattern.
6. The method of claim 5 further comprising the step of passivating.
7. The method of claim 5 further comprising the step of creating signal processing circuitry in said active silicon layer, said signal processing circuitry being in electrical communication with said PIN diode anode contact and said PIN diode cathode contact.
8. The method of claim 1 further comprising the step of passivating.
9. The method of claim 8 further comprising the step of creating signal processing circuitry in said active silicon layer, said signal processing circuitry being in electrical communication with said PIN diode anode contact and said PIN diode cathode contact.
10. The method of claim 1 further comprising the step of creating signal processing circuitry in said active silicon layer, said signal processing circuitry being in electrical communication with said PIN diode anode contact and said PIN diode cathode contact.