# How Amorphous Silicon Changed Solar Power > This 1976 patent describes using a specific form of non-crystalline silicon to create cheap, thin semiconductor devices like solar cells. - **Patent:** US 4064521 - **Original title:** Semiconductor device having a body of amorphous silicon - **Owner:** RCA Corp - **Granted:** 1977 - **Status:** Public domain (expired) - **Times cited:** 197 - **Field:** energy, semiconductors, consumer_electronics ## What it does The patent details a method for creating semiconductor devices using amorphous silicon, which is silicon that lacks a rigid, repeating crystal structure. By using a process called glow discharge in silane gas, the inventors created a material that could form effective electronic junctions. Specifically, the patent claims devices where this amorphous silicon is paired with metallic regions or other semiconductor layers to create barriers that generate a space charge region. This allows the device to capture solar radiation and convert it into electricity, or function as a basic electronic component. ## What it does NOT cover - Does not cover crystalline silicon, which is the standard material used in most traditional computer chips. - Does not cover any manufacturing process that does not use a glow discharge in silane gas. - Does not cover devices where the amorphous silicon layer is thicker than one micron if the specific electronic performance claims are not met. ## The clever bit The invention turned the 'defect' of amorphous silicon—its lack of a crystal lattice—into a feature by showing that it could be doped and manipulated to create functional junctions at a fraction of the cost of crystalline alternatives. ## Real-world examples 1. Thin-film solar panels 2. Pocket calculator solar cells 3. Flexible solar modules ## Why it matters Before this, solar cells were almost exclusively made from expensive, high-purity crystalline silicon. This patent proved that a disordered, cheaper-to-produce material could still perform the essential task of generating electricity from light, paving the way for the thin-film solar panels we see today. ## Frequently asked questions ### What does How Amorphous Silicon Changed Solar Power cover? This 1976 patent describes using a specific form of non-crystalline silicon to create cheap, thin semiconductor devices like solar cells. ### Who owns patent US 4064521? RCA Corp owns this patent, granted in 1977. ### When does this patent expire? This patent has expired and is now in the public domain — anyone can use the invention freely. ### What is patent US 4064521 cited by? This patent has been cited by 197 later patents that build on its ideas. ### What problem does this patent solve? Before this, solar cells were almost exclusively made from expensive, high-purity crystalline silicon. This patent proved that a disordered, cheaper-to-produce material could still perform the essential task of generating electricity from light, paving the way for the thin-film solar panels we see today. ### What does this patent NOT cover? Does not cover crystalline silicon, which is the standard material used in most traditional computer chips. **Full plain-English explainer:** https://patentbrief.org/patent/us/4064521/semiconductor-device-having-a-body-of-amorphous-silicon **Original patent:** https://patents.google.com/patent/US4064521 --- _Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._ ## Related patents Semantically similar inventions in the PatentBrief corpus: - [How the First Practical Silicon Solar Cell Works](https://patentbrief.org/patent/us/2780765/solar-cell-photovoltaic) — A 1954 invention by Bell Labs researchers that created the first silicon-based solar cell capable of converting sunlight into enough electricity to power everyday devices. - [The Invention of the Modern Field-Effect Transistor](https://patentbrief.org/patent/us/3102230/mosfet-field-effect-transistor) — This 1960 patent describes the fundamental structure of the MOSFET, the tiny electronic switch that powers every modern computer processor. - [The Invention of the Junction Transistor](https://patentbrief.org/patent/us/2569347/junction-transistor) — William Shockley's 1951 patent for the junction transistor, the fundamental building block of all modern digital electronics. - [How Liquid Crystal Displays (LCDs) Were Invented](https://patentbrief.org/patent/us/3322485/lcd-liquid-crystal-display) — This 1962 patent describes the first practical way to use organic liquid crystals to create a display that scatters light when an electric current is applied. - [How Robert Noyce Invented the Modern Integrated Circuit](https://patentbrief.org/patent/us/2981877/noyce-planar-integrated-circuit) — Robert Noyce's 1959 patent for a semiconductor device that uses evaporated metal leads to connect components directly on a single silicon chip.