Strained thin film heterojunction, preparation method and application

Abstract

The invention discloses a strained thin film heterojunction, a preparation method and application, and belongs to the technical field of semiconductor thin film preparation. The preparation method comprises the following steps that a high-purity silicon target, a high-purity germanium target, a cadmium target, a high-purity boron target and high-purity intrinsic monocrystalline germanium are put into a multi-target co-sputtering magnetron sputtering vacuum chamber; the high-purity intrinsic monocrystalline germanium is heated to 250 DEG C; the silicon target, the germanium target and the borontarget are each pre-sputtered for 20 min; the cadmium target is sputtered, a cadmium transitional layer is deposited, and a Si0.25Ge0.75 layer is deposited through co-sputtering; and after the temperature of 250 DEG C is maintained for an hour, cooling is conducted to room temperature, the deposited Si0.25Ge0.75 thin film heterojunction is obtained, and then annealing is conducted, wherein the whole process is carried out in inert gas. The method can be used for quickly preparing the Si0.25Ge0.75 / Ge strained thin film heterojunction which has a uniform global strain.

Description

technical field [0001] The invention belongs to the technical field of semiconductor thin film preparation, in particular to a Si 0.25 Ge 0.75 / Ge strained thin film heterojunction, preparation method and application. Background technique [0002] Group IV semiconductor materials have a wide range of applications in the fields of microelectronics and solar cells. The doping of magnetic ions has great prospects in information processing and storage, and Group IV semiconductor thin films with uniformly doped magnetic particles are one of the ideal candidate materials for spin devices. With the development of science and technology, future high-performance microelectronic devices should simultaneously meet the multifunctional requirements of high speed, low power consumption and room temperature ferromagnetism. However, the poor electrical properties of existing silicon-based semiconductor materials, especially the low hole mobility, will not only hinder the further improvem...

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Problems solved by technology

However, the critical thickness of the thin film heterojunction grown in this way is only about 30nm. When the thickness of the thin film heterojunction exceeds the critical thickness, a higher dislocation density will always be introduced due to the excessive lattice mismatch (M.L. Lee, E.A.Fitzgerald, M.T.Bulsara, M.T.Currie, A.Lochtefeld, Strained Si, SiGe, and Ge Channels for High~mobilityMetal~oxide~semiconductor Field~effect Transistors, J.Appl.Phys.97(2005)011101.)

The microstructural defects formed by the accumulation of these dislocations will further lead to local stress and strain concentration, and even cause microcracks or protrusions during material processing (G.Abadias, E.Chason, J.Keckes, M.Sebastiani, G.B.Thompson, more serious Yes, the stress and strain obtained by the lattice mismatch method decay rapidly along the depth of the thin film heterojunction (S.W.Bedell, A.Khakifirooz, D.K.Sadana, Strainscaling for CMOS, MRS Bull.39(2014) 131~137. ), as the thickness of the film heterojunction increases, the strain becomes smaller and smaller, thus limiting the further improvement of the hole mobility

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