Transverse-structure IMPATT diode and preparation method thereof

Abstract

The invention discloses a transverse-structure IMPATT diode and a preparation method of the IMPATT diode. The IMPATT diode includes: a substrate layer, an epitaxial layer, a drift layer, an n-AlGaN barrier layer, an n+-GaN barrier layer, a left ohmic contact layer, a right ohmic contact layer, a left ohmic contact electrode, a right ohmic contact electrode, a passivation layer and a Schottky contact electrode. When the transverse-structure IMPATT diode is electrified, the current direction is along the transverse direction of the epitaxial layer; the drift layer is a two-dimensional electrongas thin layer formed on the top of the epitaxial layer, and the transition process is limited in the drift layer rather than in a body material. The IMPATT provided by the invention improves the oscillation frequency, the transverse circuit compatibility and the frequency flexibility compared with a traditional vertical-structure IMPATT by utilizing a transverse structure under the same material.

Description

technical field [0001] The invention belongs to the technical field of semiconductors, and relates to a lateral structure IMPATT diode and a preparation method thereof. Background technique [0002] Avalanche diode (IMPATT) is a semiconductor device that uses impact ionization in semiconductors to generate charge packets, and the charge packets pass through to generate negative resistance at a certain frequency. Because avalanche will produce avalanche delay, carriers drifting inside the device through a finite time will produce transit time delay. The superposition of these two delays will cause the establishment of avalanche current to lag behind the terminal voltage, thus generating negative resistance. When the sum of these two delays falls within the range of 1 / 4 cycle to 3 / 4 cycle (90° to 270° phase difference), the dynamic resistance of the diode is negative at this time. As one of the most efficient and powerful microwave solid-state sources, IMPATT diodes have rece...

AI Technical Summary

Problems solved by technology

However, the forbidden band width of GaN material is too large, which is 3.4eV. The typical value of the metal work function available in the current process is generally around 4 to 5eV, and it is difficult to form a lower metal-P-type GaN barrier height difference.

Second, the free hole concentration in P-type doped GaN is too low, and it is difficult to obtain a high free hole concentration even with a high doping level

To sum up, in the traditional GaN-based IMPATT with vertical structure, it is difficult to form high-quality P-type ohmic contacts due to the immature manufacturing technology of P-type GaN, which limits the concentration of charge packets generated by impact ionization, and seriously Restricts the working performance of the traditional vertical structure IMPATT

Images