Epitaxial growth of SiGe on Si substrate by printing and firing of Al–Ge mixed paste

Abstract

We report on a simple liquid-phase epitaxy (LPE) of SiGe on Si (100) substrate based on printing and firing. LPE was performed using an Al-Ge mixed paste screen-printed on a Si (100) substrate followed by annealing above the Al-Ge eutectic temperature in air or in an Ar atmosphere. In the case of annealing in air at 800 °C, SiGe was formed between the mixed paste and the surface of the Si substrate. However, a wave-like oxide film was confirmed at the SiGe/Si interface, which hindered the growth of SiGe. On the other hand, annealing in the Ar atmosphere at 800 °C led to the successful formation of a more continuous, thicker SiGe film by suppressing the oxidation of Al. It can be concluded that LPE growth using printing and firing of Al-Ge mixed paste is a suitable method to grow SiGe with a low-cost and simple high-speed process.

Effect of annealing ambient on SiGe layer formation using Al–Ge paste for III–V solar cell application

“…This method is a simple process using a conventional screen-printer and a furnace, and it has been confirmed that uniform SiGe layers with a thickness of more than 20 μm can be formed in a short processing time. [24][25][26][27][28] In this method, a liquid phase of Al-Ge-Si can be formed at a temperature below the mp of Si by screen-printing Al-Ge paste on a Si substrate. After the liquid phase is formed at high temperatures, cooling leads to the epitaxial growth of a SiGe layer at the interface of the Si substrate.…”

“…The properties of the formed SiGe layer have been found to strongly depend on fabrication parameters such as the Al/Ge ratio of the Al-Ge paste and the annealing temperature profile. 25,26,28) In this study, the effect of ambient gas during annealing on the growth of SiGe layers was investigated in order to determine the parameters of SiGe layer formation in liquid phase growth on Si substrates using Al-Ge paste.…”

Epitaxial growth of SiGe films by annealing Al–Ge alloyed pastes on Si substrate

“…Moreover, this process does not need toxic gases, and epitaxial growth can be realized in a non-vacuum atmosphere. However, the SiGe film grown on Si(001) has undulated interface derived from spearing reaction 28 and non-uniform dissolution of Si substrate. The spearing reaction is induced by individual Al particles that reduce the native SiO 2 on the Si substrate 31 , 32 .…”

“…Recently, instead of conventional processes such as CVD and MBE, we have realized epitaxial growth of SiGe films having ~ 10 µm thickness by a process using original Al-Ge mixed pastes for screen printing on Si substrates and subsequent annealing in Ar ambient [27][28][29] . This method is a simple, low-cost, and high-speed approach that uses a melting point depression caused by the eutectic reaction, as seen in the Al-Si-Ge ternary phase diagram of Fig.…”

Fabrication of group IV semiconductor alloys on Si substrate applying Al paste with screen-printing

“…Recently, our group demonstrated 10 μm thick and almost uniform relaxed SiGe layer with over 20% Ge content by a screen-printing technique. [18][19][20] The screen-printing technique with a fast annealing process is well established in today's crystalline Si solar cell industry and has contributed to the expansion of their market share all over the world.…”