Initial Stages of Epitaxial Growth of GaP on Si with AsH₃ Preflow

Abstract

A previous paper reported that when GaP epilayers are grown on Si substrates, an As-stabilized surface made by AsH3 preflow before growth prevents many defects from generating at the GaP/Si interface, and that consequently, the crystalline quality of GaP epilayers is markedly improved. This letter describes the AsH3 preflow effect on the initial stages of GaP epitaxial growth. The relative ease with which As or P atoms are absorbed onto Si surfaces is observed using X-ray photoelectron spectroscopy. Although preflow before GaP growth causes As or P atoms to absorb onto Si surfaces, As atoms are absorbed more easily than P atoms. The initial stages of GaP epitaxial growth on Si substrates with and without AsH3 preflow are investigated using high-resolution scanning electron microscopy and transmission electron microscopy. This confirms that AsH3 preflow suppresses island growth, allowing GaP epilayers to grow two-dimensionally, and also reduces the GaP-Si interfacial energy.

Selective Area Growth of InP in Shallow-Trench-Isolated Structures on Off-Axis Si(001) Substrates

“…This indeed leads to a much smoother surface, agreeing with previous work. [14][15][16] This further supports the idea that As atoms are preferred for a full monolayer coverage of the Ge surface that facilitates the subsequent growth of a III-V layer. Also, Fig.…”

“…15 For the growth of GaP on Si͑100͒, baking in an As ambient results in an improved crystalline quality of the GaP layers. 16 This results from the fact that As can more easily form a closed monolayer on a Si surface compared to P. 16 Similar mechanisms should apply to Ge surfaces. The nucleation of InP on a Ge surface requires a full monolayer coverage of a group V element to convert the nonpolar Ge surface into a polar surface.…”

Direct Heteroepitaxy and Selective Area Growth of GaP and GaAs on Si by Hydride Vapor Phase Epitaxy

“…[ 49,50 ] This effect has been attributed to improved wetting of Si surfaces by GaP when the Si is terminated by As compared with P, promoting layer‐by‐layer growth. [ 51 ] To summarize, the growth of a GaP buffer layer resulted in island‐like growth with rough morphology on both Si(100) and Si(111) (Figure 1a,b). This resulted in poor morphology and crystalline quality for GaP growths using the 2‐step process on both Si(100) and Si(111) (Figure 2a–d).…”

MOVPE growth of GaP on Si with As initial coverage

“…A common approach is the formation of a virtual III-V substrate, by growing a GaP nucleation layer on the Si-substrate, acting as a template for the growth of the complete III-V semiconductor structure since this heteroepitaxial growth (GaP/Si) has the minimum lattice mismatch for a III-V on Si, i.e 0.36%. However, the system (GaP/Si) presents certain challenges that degrade the quality of the layers: i) the epitaxial strain or three dimensional growth, that leads to the formation of defects at the GaP/ Si heterointerface or/and in the epitaxial layer [4][5][6]; ii) the growth of a polar III-V semiconductor (i.e. GaP) on a nonpolar substrate (i.e.…”

“…GaP) on a nonpolar substrate (i.e. Si) induces the formation of antiphase domains (APD) [5][6][7][8][9], which, if they are not annihilated or avoided will be detrimental for devices; and iii) the unwanted cross doping through the interface [9]. Recent and very promising studies opened the possibility of modifying the surface of a Si-substrate by As-coverage (close to 1 ML) and thermal treatments previous to the GaP deposit [10].…”