Groove PiN type beta irradiation battery with gate electrode surface field and preparation method of groove PiN type beta irradiation battery

Abstract

The invention relates to a groove PiN type beta irradiation battery with a gate electrode surface field and a preparation method thereof, and the irradiation battery comprises a PiN unit and a radioactive isotope unit located on the PiN unit. Each PiN unit comprises an N-type doped 4H-SiC substrate, an N-type doped 4H-SiC epitaxial layer, a P-type doped 4H-SiC epitaxial layer, an N-type ohmic contact electrode, an isolation passivation layer, a groove passivation layer, a P-type ohmic contact electrode, a plurality of groove regions and a gate electrode, and the groove regions penetrate through the P-type doped 4H-SiC epitaxial layer and are distributed in the N-type doped 4H-SiC epitaxial layer at intervals; the P-type doped 4H-SiC epitaxial layer is enabled to to form a distributed P-type region; the groove passivation layer covers the surface of the groove region; the P-type ohmic contact electrode is located on the distributed P-type region and is adjacent to the isolation passivation layer; and the gate electrode is positioned above the groove passivation layer and is distributed with the P-type ohmic contact electrode in a staggered manner. The irradiation battery achieves the purpose of improving the energy conversion efficiency of the beta irradiation battery.

Description

technical field [0001] The invention belongs to the technical field of microelectronics, and in particular relates to a trench PiN type beta irradiation battery with a grid electrode surface field and a preparation method. Background technique [0002] Micronuclear batteries or radioisotope batteries have many advantages such as small size, light weight, long service life, easy integration, and work not affected by the external environment. They can be used to solve aerospace deep space exploration, artificial heart pacemakers, portable mobile electronic products , implanted microsystems, etc., are considered to be one of the ideal long-term energy sources for micro-electric applications such as micro-electro-mechanical systems (MEMS) and sensors. [0003] β-irradiated battery is a kind of 3 H. 63 Ni and 147 A semiconductor isotope battery that outputs electrical energy through the radiant volt effect of beta (β-Particle) rays emitted by radioactive isotopes such as Pm. ...

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Problems solved by technology

[0005] However, in existing reports, the energy conversion efficiency of silicon carbide diode devices under ideal conditions can reach 23.5%, which is much higher than the experimental results. The main reason is that the energy deposition of β rays in silicon carbide materials decays exponentially with the incident depth. , the electron-hole pairs generated by a large amount of irradiation are located within 1 μm of the device surface, which leads to the surface recombination of SiC PiN devices and the thickness of the dead layer in the P-type region will have a significant impact on its energy conversion efficiency

[0006] See figure 1 , figure 1 A schematic structural diagram of a conventional silicon carbide PiN-type β-irradiated battery provided for the prior art. The PIN nuclear battery is sequentially composed of a radioactive source 60, a P-type ohmic contact electrode 50, and a P-type highly doped SiC layer. 30. Intrinsic i-layer 20, n-type highly doped SiC substrate 10 and N-type ohmic contact electrode 40; the surface recombination of the P-type highly doped SiC layer 30 on the one hand reduces the electrons generated by β rays in the semiconductor- The collection efficiency of the hole pairs leads to a decrease in the short-circuit current Isc, and on the other hand increases the saturation current of the PiN device, resulting in a decrease in the open-circuit voltage Voc and the fill factor FF; its relatively thick P-type highly doped SiC layer 30 While increasing the dead layer loss, it will further enhance the negative impact of surface recombination

However, the maximum output power of the β-irradiated battery Pout=FF·Isc·Voc, so the surface recombination and the thickness of the dead layer in the P-type region will limit the energy conversion efficiency of the silicon carbide PiN-type β-irradiated battery

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