Semiconductor device with a bulk single crystal on a substrate
Device and method of forming a device in which a substrate ( 10 ) is fabricated with at least part of an electronic circuit for processing signals. A bulk single crystal material ( 14 ) is formed on the substrate, either directly on the substrate ( 10 ) or with an intervening thin film layer or transition region ( 12 ). A particular application of the device is for a radiation detector.
1. A method of forming a device for detection of high energy photons comprising fabricating a substrate with at least part of an electronic circuit for processing electrical signals, and depositing a bulk single crystal material for absorbing the high energy photons and generating the electrical signals onto the substrate, the bulk single crystal material being deposited epitaxially such that the electrical signals generated within the bulk single crystal material can pass through to the underlying substrate to be processed by the electronic circuit within the substrate, in which the device is suitable for detection of x-rays, gamma rays, or both x-rays and gamma rays, and the bulk single crystal material is cadmium telluride, cadmium zinc telluride or cadmium manganese telluride.
2. The method according to claim 1 , in which the bulk single crystal material is deposited on the substrate before fabrication of the electronic circuit in the substrate.
3. The method according to claim 1 , in which the bulk single crystal material is deposited on the substrate after fabrication of the electronic circuit in the substrate.
4. The method according to claim 1 , in which the substrate is formed from a silicon or gallium arsenide material.
5. The method according to claim 1 , in which the electronic circuit is formed in the substrate by doping regions of the substrate using ion implantation, diffusion techniques, lithography or etching.
6. The method according to claim 1 , in which the electronic circuit includes an application-specific integrated circuit.
7. The method according to claim 1 , further including providing metal contact regions on a surface of the substrate that can be used to output processed electrical signals.
8. The method according to claim 1 , including the step of forming an interfacial region between the substrate and the bulk single crystal material.
9. The method according to claim 8 , in which the interfacial region is formed in a single process using a vapour phase deposition method.
10. The method according to claim 1 , further comprising forming a metal layer on the bulk single crystal material.
11. The method according to claim 1 , in which the bulk single crystal material is deposited to a thickness of from 0.007 cm to 3.5 cm.